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 A187655 #10 Oct 16 2021 10:19:03
%S A187655 1,2,15,194,3631,89712,2764268,102207394,4411265695,217707856946,
%T A187655 12092696127691,746552539553152,50708165735187572,3757864633323765824,
%U A187655 301719332111553586612,26089939284112306045362,2417245528055399202851119
%N A187655 Self-convolution of the central Stirling numbers of the second kind.
%C A187655 The sequence of the central Stirling numbers of the second kind is 1, 1, 7, 90, 1701,... with offset 0 (see A007820).
%F A187655 a(n) = sum_{k=0..n} A048993(2k,k)*A048993(2n-2k,n-k).
%F A187655 a(n) ~ 2^(2*n+1/2) * n^(n-1/2) / (sqrt(Pi*(1-c)) * exp(n) * (c*(2-c))^n), where c = -LambertW(-2*exp(-2)) = 0.4063757399599599... . - _Vaclav Kotesovec_, May 20 2014
%p A187655 seq( add(combinat[stirling2](2*k,k) *combinat[stirling2](2*(n-k),n-k) ,k=0..n), n=0..12);
%t A187655 Table[Sum[StirlingS2[2k, k]StirlingS2[2n - 2k, n - k], {k, 0, n}], {n, 0, 16}]
%o A187655 (Maxima) makelist(sum(stirling2(2*k,k)*stirling2(2*n-2*k,n-k),k,0,n),n,0,12);
%Y A187655 Cf. A187656.
%K A187655 nonn,easy
%O A187655 0,2
%A A187655 _Emanuele Munarini_, Mar 12 2011