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 A263445 #20 May 18 2022 09:36:18
%S A263445 1,1,-1,4,-36,600,-16584,705600,-43751232,3790108800,-443539877760,
%T A263445 68218849036800,-13478425925184000,3355402067989171200,
%U A263445 -1035218714714606822400,390189256983139461120000,-177430554756972746695065600,96269372301568677170319360000
%N A263445 a(n) = (2n+1)*(n+1)!*Bernoulli(2n).
%H A263445 Robert Israel, <a href="/A263445/b263445.txt">Table of n, a(n) for n = 0..210</a>
%H A263445 <a href="/index/Be#Bernoulli">Index entries for sequences related to Bernoulli numbers.</a>
%F A263445 a(n) = (2n+1)*(n+1)!*Bernoulli(2n).
%F A263445 a(n) ~ (-1)^(n+1)*8*sqrt(2)*n^3*(n/e)^(3*n)*Pi^(1-2*n). - _Vladimir Reshetnikov_, Sep 05 2016
%p A263445 seq((2*n+1)*(n+1)!*bernoulli(2*n), n=0..50); # _Robert Israel_, Oct 18 2015
%t A263445 Table[(2n + 1) (n + 1)! BernoulliB[2n], {n, 0, 17}]
%o A263445 (PARI) vector(30, n, n--; (2*n+1)*(n+1)!*bernfrac(2*n)) \\ _Altug Alkan_, Oct 18 2015
%o A263445 (Python)
%o A263445 from math import factorial
%o A263445 from sympy import bernoulli
%o A263445 def A263445(n): return (2*n+1)*factorial(n+1)*bernoulli(2*n) # _Chai Wah Wu_, May 18 2022
%Y A263445 Bernoulli numbers are A000367/A002445. Cf. A004193, A001332, A000182, A001469.
%K A263445 sign
%O A263445 0,4
%A A263445 _Vladimir Reshetnikov_, Oct 18 2015