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 A383208 #8 Apr 19 2025 10:04:18
%S A383208 0,0,0,1,18,245,3120,39697,517790,6999785,98520060,1445923149,
%T A383208 22129416210,352932509085,5859167661256,101122879922313,
%U A383208 1811960841148774,33662625853200337,647550189266734452,12881675626292023173,264677402162135670554,5610552395871699336453
%N A383208 Expansion of e.g.f. (exp(f(x)) - 1)^3 / 6, where f(x) = (exp(2*x) - 1)/2.
%F A383208 a(n) = Sum_{k=3..n} 2^(n-k) * Stirling2(n,k) * Stirling2(k,3).
%o A383208 (PARI) a(n) = sum(k=3, n, 2^(n-k)*stirling(n, k, 2)*stirling(k, 3, 2));
%Y A383208 Column k=3 of A383206.
%Y A383208 Cf. A000559.
%K A383208 nonn
%O A383208 0,5
%A A383208 _Seiichi Manyama_, Apr 19 2025