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 A361489 #25 Mar 14 2023 12:59:34
%S A361489 1,1,2,6,19,72,313,1472,7612,42679,255515,1632710,11065057,79065807,
%T A361489 594174922,4679473130,38500353667,330172915164,2944613004359,
%U A361489 27253908250340,261328607398332,2591724561444621,26545170005412613,280411070646125638
%N A361489 Expansion of e.g.f. exp(exp(x) - 1 + x^3/6).
%F A361489 a(0) = a(1) = 1, a(2) = 2; a(n) = binomial(n-1,2) * a(n-3) + Sum_{k=1..n} binomial(n-1,k-1) * a(n-k).
%o A361489 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(exp(x)-1+x^3/6)))
%Y A361489 Cf. A124504, A360991.
%K A361489 nonn,easy
%O A361489 0,3
%A A361489 _Seiichi Manyama_, Mar 14 2023