5 internet doctests failing in src/sage/databases/oeis.py

[seblabbe]

On Ubuntu 18.04 running 9.5.beta3, the command

$ sage -t --optional=sage,internet src/sage/databases/oeis.py

gives

Using --optional=internet,sage
Doctesting 1 file.
sage -t --random-seed=0 src/sage/databases/oeis.py
**********************************************************************
File "src/sage/databases/oeis.py", line 347, in sage.databases.oeis.OEIS
Failed example:
    fibo.comments()[1]                        # optional -- internet
Expected:
    "F(n+2) = number of binary sequences of length n that have no
    consecutive 0's."
Got:
    'In keeping with historical accounts (see the references by P. Singh and S. Kak), the generalized Fibonacci sequence a, b, a + b, a + 2b, 2a + 3b, 3a + 5b, ... can also be described as the Gopala-Hemachandra numbers H(n) = H(n-1) + H(n-2), with F(n) = H(n) for a = b = 1, and Lucas sequence L(n) = H(n) for a = 2, b = 1. - Lekraj Beedassy, Jan 11 2015'
**********************************************************************
File "src/sage/databases/oeis.py", line 542, in sage.databases.oeis.OEIS.find_by_subsequence
Failed example:
    oeis.find_by_subsequence([2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377]) # optional -- internet
Expected:
    0: A000045: Fibonacci numbers: F(n) = F(n-1) + F(n-2) with F(0) = 0 and F(1) = 1.
    1: A212804: Expansion of (1 - x)/(1 - x - x^2).
    2: A177194: Fibonacci numbers whose decimal expansion does not contain any digit 0.
Got:
    0: A000045: Fibonacci numbers: F(n) = F(n-1) + F(n-2) with F(0) = 0 and F(1) = 1.
    1: A212804: Expansion of (1 - x)/(1 - x - x^2).
    2: A020695: Pisot sequence E(2,3).
**********************************************************************
File "src/sage/databases/oeis.py", line 1506, in sage.databases.oeis.OEISSequence.references
Failed example:
    w.references()                        # optional -- internet
Expected:
    ...A. H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 52.
    ...
Got:
     0: N. G. W. H. Beeger, On the Congruence (p-1)! == -1 (mod p^2), Messenger of Mathematics, Vol. 49 (1920), pp. 177-178.
     1: Albert H. Beiler, Recreations in the Theory of Numbers, Dover, NY, 1964, p. 52.
     2: Calvin C. Clawson, Mathematical Mysteries, Plenum Press, 1996, p. 180.
     3: Richard Crandall and Carl Pomerance, Prime Numbers: A Computational Perspective, Springer, NY, 2001; see p. 29.
     4: G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, th. 80.
     5: G. B. Mathews, Theory of Numbers Part I., Cambridge: Deighton, Bell and Co., London: George Bell and Sons, 1892, page 318.
     6: Paulo Ribenboim, My Numbers, My Friends: Popular Lectures on Number Theory, Springer Science & Business Media, 2000, ISBN 0-387-98911-0.
     7: Paulo Ribenboim, The Book of Prime Number Records. Springer-Verlag, NY, 2nd ed., 1989, p. 277.
     8: N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
     9: Ilan Vardi, Computational Recreations in Mathematica. Addison-Wesley, Redwood City, CA, 1991, p. 73.
    10: David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, 163.
**********************************************************************
File "src/sage/databases/oeis.py", line 1639, in sage.databases.oeis.OEISSequence.cross_references
Failed example:
    nbalanced.cross_references(fetch=True)    # optional -- internet
Expected:
    0: A049703: a(0) = 0; for n>0, a(n) = A005598(n)/2.
    1: A049695: Array T read by diagonals; ...
    2: A103116: a(n) = A005598(n) - 1.
    3: A000010: Euler totient function phi(n): count numbers <= n and prime to n.
Got:
    0: A049703: a(0) = 0; for n>0, a(n) = A005598(n)/2.
    1: A049695: Array T read by diagonals; T(i,j) is the number of nonnegative slopes of lines determined by 2 lattice points in [ 0,i ] X [ 0,j ] if i > 0; T(0,j)=1 if j > 0; T(0,0)=0.
    2: A103116: a(n) = Sum_{i=1..n} (n-i+1)*phi(i).
    3: A000010: Euler totient function phi(n): count numbers <= n and prime to n.
**********************************************************************
File "src/sage/databases/oeis.py", line 1724, in sage.databases.oeis.OEISSequence.comments
Failed example:
    f.comments()[:3]                      # optional -- internet
Expected:
    0: Also sometimes called Lamé's sequence.
    1: F(n+2) = number of binary sequences of length n that have no consecutive 0's.
    2: F(n+2) = number of subsets of {1,2,...,n} that contain no consecutive integers.
Got:
    0: D. E. Knuth writes: "Before Fibonacci wrote his work, the sequence F_{n} had already been discussed by Indian scholars, who had long been interested in rhythmic patterns that are formed from one-beat and two-beat notes. The number of such rhythms having n beats altogether is F_{n+1}; therefore both Gopāla (before 1135) and Hemachandra (c. 1150) mentioned the numbers 1, 2, 3, 5, 8, 13, 21, ... explicitly." (TAOCP Vol. 1, 2nd ed.) - _Peter Luschny_, Jan 11 2015
    1: In keeping with historical accounts (see the references by P. Singh and S. Kak), the generalized Fibonacci sequence a, b, a + b, a + 2b, 2a + 3b, 3a + 5b, ... can also be described as the Gopala-Hemachandra numbers H(n) = H(n-1) + H(n-2), with F(n) = H(n) for a = b = 1, and Lucas sequence L(n) = H(n) for a = 2, b = 1. - Lekraj Beedassy, Jan 11 2015
    2: Susantha Goonatilake writes: "[T]his sequence was well known in South Asia and used in the metrical sciences. Its development is attributed in part to Pingala (200 BC), later being associated with Virahanka (circa 700 AD), Gopala (circa 1135), and Hemachandra (circa 1150)—all of whom lived and worked prior to Fibonacci." (Toward a Global Science: Mining Civilizational Knowledge, p. 126) - _Russ Cox_, Sep 8 2021
**********************************************************************
5 items had failures:
   1 of  20 in sage.databases.oeis.OEIS
   1 of   3 in sage.databases.oeis.OEIS.find_by_subsequence
   1 of   5 in sage.databases.oeis.OEISSequence.comments
   1 of   7 in sage.databases.oeis.OEISSequence.cross_references
   1 of   5 in sage.databases.oeis.OEISSequence.references
    [289 tests, 5 failures, 35.09 s]
----------------------------------------------------------------------
sage -t --random-seed=0 src/sage/databases/oeis.py  # 5 doctests failed
----------------------------------------------------------------------

Component: doctest coverage

Author: David Coudert

Branch/Commit: 9883de7

Reviewer: Sébastien Labbé

Issue created by migration from https://trac.sagemath.org/ticket/32695

[dcoudert]

Author: David Coudert

[dcoudert]

comment:1

this fixes the doctests, but is not robust to future changes in the database.

---

New commits:

9883de7

trac #32695: fix internet doctests

[dcoudert]

Commit: 9883de7

[dcoudert]

Branch: public/database/32695_oeis

[seblabbe]

Reviewer: Sébastien Labbé

[seblabbe]

comment:2

works for me, patchbot is green with respect to everything except for 1 unrelated doctest failure.

[vbraun]

Changed branch from public/database/32695_oeis to 9883de7