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 A076813 #23 Apr 16 2025 22:30:37
%S A076813 2,4,0,7,4,4,6,5,5,4,7,9,0,3,2,8,5,1,4,7,0,9,4,8,6,6,5,6,2,2,3,0,2,2,
%T A076813 7,2,5,5,8,2,2,6,6,4,9,0,3,7,9,8,4,4,1,8,8,6,9,3,3,9,8,3,3,3,5,5,7,0,
%U A076813 4,7,0,2,8,1,3,7,0,7,2,2,3,5,6,9,1,5,9,0,3,0,1,2,6,6,3,5,2,1,5,6,7,7
%N A076813 Decimal expansion of Sum_{k>=1} zeta(2k)/k! = 2.40744...
%H A076813 G. C. Greubel, <a href="/A076813/b076813.txt">Table of n, a(n) for n = 1..10000</a>
%H A076813 J. Sondow and E. W. Weisstein, <a href="https://mathworld.wolfram.com/RiemannZetaFunction.html">MathWorld: Riemann Zeta Function</a>
%e A076813 2.40744655479032851470948665622302272558226649037984418869339833...
%p A076813 evalf(Sum(exp(1/n^2)-1, n=1..infinity), 120); # _Vaclav Kotesovec_, Mar 04 2016
%t A076813 rd[k_] := rd[k] = RealDigits[ N[ Sum[ Zeta[2n]/n!, {n, 1, 2^k}], 105]][[1]][[1 ;; 102]]; rd[k = 4]; While[ rd[k] != rd[k-1], k++]; rd[k] (* _Jean-François Alcover_, Oct 29 2012 *)
%o A076813 (PARI) suminf(n=1, zeta(2*n)/n!) \\ _Michel Marcus_, Mar 20 2017
%K A076813 nonn,cons
%O A076813 1,1
%A A076813 _Eric W. Weisstein_, Oct 16 2002