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 A051720 #25 Jul 02 2025 16:01:58
%S A051720 1,1,2,2,-1,-4,-1,8,7,-44,-2663,368,1247,-244,-1511,43416,1623817,
%T A051720 -276356,-10405289,-21376,21491081,32209348,-2523785339,-107638072,
%U A051720 1827648887,842271812,-11254630547,-17380760743952,596303510772251
%N A051720 Numerators of column 3 of table described in A051714/A051715.
%H A051720 Seiichi Manyama, <a href="/A051720/b051720.txt">Table of n, a(n) for n = 0..626</a>
%H A051720 M. Kaneko, <a href="https://cs.uwaterloo.ca/journals/JIS/VOL3/KANEKO/AT-kaneko.html">The Akiyama-Tanigawa algorithm for Bernoulli numbers</a>, J. Integer Sequences, 3 (2000), #00.2.9.
%F A051720 a(n) = numerator(n! * [x^n] f(x)) where f(x) =(x*exp(4*x))/(1-exp(x))^4+13/(3*(1-exp(x)))-7/(2*(1-exp(x))^2)+1/(1-exp(x))^3-13/12. - _Vladimir Kruchinin_, Nov 03 2015
%t A051720 a[0, k_] := 1/(k+1); a[n_, k_] := a[n, k] = (k+1)*(a[n-1, k] - a[n-1, k+1]); a[n_] := a[n, 3] // Numerator; Table[a[n], {n, 0, 28}] (* _Jean-François Alcover_, Sep 17 2012 *)
%Y A051720 Cf. A051721.
%K A051720 sign,easy,nice
%O A051720 0,3
%A A051720 _N. J. A. Sloane_
%E A051720 More terms from _James Sellers_, Dec 08 1999