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 A308458 #15 May 29 2019 12:04:20
%S A308458 1,1,23,3994,9745169,470126386536,558542572785461515,
%T A308458 19342808645467142112096240,22528399370853856386499346950471953,
%U A308458 999999999774716004550606847948627702867525440,1890591424701781041871514584507296209311760279398415565711
%N A308458 Expansion of e.g.f. log(Sum_{k>=0} k^binomial(k,2) * x^k / k!).
%H A308458 Seiichi Manyama, <a href="/A308458/b308458.txt">Table of n, a(n) for n = 1..36</a>
%e A308458 E.g.f.: x + x^2/2! + 23*x^3/3! + 3994*x^4/4! + 9745169*x^5/5! + 470126386536*x^6/6! + 558542572785461515*x^7/7! + ... .
%o A308458 (PARI) N=20; x='x+O('x^N); Vec(serlaplace(log(sum(k=0, N, k^binomial(k, 2)*x^k/k!))))
%Y A308458 Cf. A001187, A001865, A003027, A054941.
%K A308458 nonn
%O A308458 1,3
%A A308458 _Seiichi Manyama_, May 27 2019