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 A377347 #9 Oct 26 2024 10:48:53
%S A377347 1,1,1,7,41,391,4509,62847,1038001,19580071,418681877,9973993855,
%T A377347 262293996777,7545559829991,235715629493005,7946944965054271,
%U A377347 287592204406672481,11120005819664145895,457514133092462477253,19957535405566629526335,920056233384401619083545
%N A377347 E.g.f. satisfies A(x) = 1 + (exp(x*A(x)^2) - 1)/A(x)^2.
%F A377347 a(n) = Sum_{k=0..floor((2*n+1)/3)} (2*n-2*k)!/(2*n-3*k+1)! * Stirling2(n,k).
%o A377347 (PARI) a(n) = sum(k=0, (2*n+1)\3, (2*n-2*k)!/(2*n-3*k+1)!*stirling(n, k, 2));
%Y A377347 Cf. A052750, A367134, A367180, A377330.
%Y A377347 Cf. A377326, A377348.
%K A377347 nonn
%O A377347 0,4
%A A377347 _Seiichi Manyama_, Oct 26 2024