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 A381758 #11 Mar 06 2025 08:28:09
%S A381758 1,8,372,24732,1925394,163883548,14773987638,1386341339430,
%T A381758 133994232166575,13248555929274096,1333732204895318366,
%U A381758 136243562694021684648,14087033746990654649067,1471456489458490198994856,155042502964505871862313879,16459391575059417875255359878
%N A381758 Expansion of exp( Sum_{k>=1} binomial(9*k-1,2*k-1) * x^k/k ).
%F A381758 a(0) = 1; a(n) = (1/n) * Sum_{k=1..n} binomial(9*k-1,2*k-1) * a(n-k).
%F A381758 G.f.: B(x)^2, where B(x) is the g.f. of A300387.
%o A381758 (PARI) my(N=20, x='x+O('x^N)); Vec(exp(sum(k=1, N, binomial(9*k-1, 2*k-1)*x^k/k)))
%Y A381758 Cf. A006013, A079489, A182960, A381751, A381752, A381753, A381757.
%Y A381758 Cf. A300387.
%K A381758 nonn,easy
%O A381758 0,2
%A A381758 _Seiichi Manyama_, Mar 06 2025