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 A356672 #9 Aug 22 2022 14:28:48
%S A356672 1,1,3,19,253,5661,188191,8983423,594848409,52174034713,5852229698971,
%T A356672 822684190381131,142739480367287893,30074750245383836149,
%U A356672 7575373641076070706423,2252600759590927171373431,783103569459739402827046321,315587346190678252431713684913
%N A356672 a(n) = n! * Sum_{k=0..n} k^(2*(n-k))/k!.
%F A356672 E.g.f: Sum_{k>=0} x^k / (k! * (1 - k^2 * x)).
%o A356672 (PARI) a(n) = n!*sum(k=0, n, k^(2*(n-k))/k!);
%o A356672 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, x^k/(k!*(1-k^2*x)))))
%Y A356672 Cf. A354436, A356673.
%Y A356672 Cf. A234568, A356628.
%K A356672 nonn
%O A356672 0,3
%A A356672 _Seiichi Manyama_, Aug 22 2022