This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A281502 #45 Feb 16 2025 08:33:39 %S A281502 6,100,351,445,691,696,790,1041,1135,1382,1386,1480,1731,1825,2073, %T A281502 2076,2170,2421,2515,2764,2766,2860,3111,3205,3455,3456,3550,3801, %U A281502 3895,4146,4240,4491,4585,4836,4837,4930,5181,5275,5526,5528,5620,5871,5965 %N A281502 Numbers m such that the numerator of Bernoulli(2m) is divisible by 691. %C A281502 6 + 345*k and 100 + 345*k are terms for k >= 0. %H A281502 Bernd C. Kellner, <a href="http://www.bernoulli.org/">The Bernoulli Number Page</a>. %H A281502 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BernoulliNumber.html">Bernoulli Number</a> %H A281502 Wikipedia, <a href="https://en.wikipedia.org/wiki/Kummer's_congruence">Kummer's congruences</a> %F A281502 a(n) = A119864(n)/2. %e A281502 Bernoulli(2*6) = -691/2730. So 6 is a term. %t A281502 Select[Range[4930],Mod[Numerator[BernoulliB[2#]], 691] == 0 &] (* _Indranil Ghosh_, Mar 11 2017 *) %o A281502 (PARI) is(n) = Mod(numerator(bernfrac(2*n)), 691)==0 \\ _Felix Fröhlich_, Jan 23 2017 %o A281502 (Python) %o A281502 from itertools import count, islice %o A281502 from sympy import bernoulli %o A281502 def A281502gen(): return filter(lambda n:not bernoulli(2*n).p % 691,count(0)) %o A281502 A281502_list = list(islice(A281502gen(),20)) # _Chai Wah Wu_, Dec 21 2021 %Y A281502 Cf. A000928, A091216, A092221 - A092229, A119864. %K A281502 nonn %O A281502 1,1 %A A281502 _Seiichi Manyama_, Jan 23 2017 %E A281502 a(12) - a(36) from _Seiichi Manyama_, Jan 24 2017 %E A281502 More terms from _Indranil Ghosh_, Mar 11 2017