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 A304857 #5 May 25 2018 17:20:34
%S A304857 1,2,17,296,8205,322412,16861408,1129044208,94262593881,9617095872812,
%T A304857 1179417144559337,171422055924510232,29164680268271517644,
%U A304857 5744954740594875376712,1297633915706481674014856,333220154688593666676579264,96542160783658837442386115393,31344432027934429150200553978812
%N A304857 a(n) = A304400(n) / n^2 for n >= 1.
%H A304857 Paul D. Hanna, <a href="/A304857/b304857.txt">Table of n, a(n) for n = 1..300</a>
%o A304857 (PARI) {a(n) = my(A=[1], m); for(i=1, n, A=concat(A, 0); m=#A; A[m] = Vec( exp( (m-1)^2 * x * Ser(A) ) * (2 - Ser(A)) )[m] ); A[n+1]/n^2}
%o A304857 for(n=1, 20, print1(a(n), ", "))
%Y A304857 Cf. A304400.
%K A304857 nonn
%O A304857 1,2
%A A304857 _Paul D. Hanna_, May 25 2018