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 A087617 #13 May 23 2021 02:41:27
%S A087617 1,2,82,10572,2860662,1330910844,947622146676,957663025230936,
%T A087617 1303349182536886566,2298001401440208011756,5095053865489946980238428,
%U A087617 13874003700656227505945514920,45517269584820569745186971856060
%N A087617 Gabcke sequence: a(0)=1; (n+1) a(n+1) = Sum_{k=0..n} 2^(4k+1) |E(2k+2)| a(n-k), where |E(2k+2)| are Euler numbers (E(2k)=(-1)^k A000364(k)).
%C A087617 Gabcke conjectured and _Juan Arias-de-Reyna_ proved that the terms are integers.
%C A087617 They also appear as the coefficients of the asymptotic expansion Sum_{n>=0} a(n) tau^(4n) of the function Re log Gamma(1/4 + i*t/2) + Pi*t/4 + (1/4)*log(t/2) - log(sqrt(2*Pi)), where tau = (1/2)*sqrt(2t).
%D A087617 W. Gabcke, Neue Herleitung und explizite Restabschaetzung der Riemann-Siegel-Formel. Dissertation, Univ. Goettingen (1979).
%H A087617 J. Arias de Reyna, <a href="http://arxiv.org/abs/math/0309190">Dynamical zeta functions and Kummer congruences</a>.
%t A087617 lambda[0] = 1; lambda[n_] := lambda[n] = Sum[2^(4 k + 1) Abs[EulerE[2k + 2]]lambda[n - 1 - k], {k, 0, n - 1}]/n
%K A087617 easy,nonn,nice
%O A087617 0,2
%A A087617 _Juan Arias-de-Reyna_, Sep 12 2003