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 A357146 #11 Sep 15 2022 11:44:40
%S A357146 1,1,1,7,49,301,6241,74131,1722337,46346329,1090339201,48905462431,
%T A357146 1584330498961,81705172522117,4191355357015009,223743062044497451,
%U A357146 16563314120270608321,1027165911865738200241,91346158358120706564097,7395168869747626389974839
%N A357146 a(n) = n! * Sum_{k=0..floor(n/2)} (n - 2*k)^(2*k)/(n - 2*k)!.
%F A357146 E.g.f.: Sum_{k>=0} x^k / (k! * (1 - (k*x)^2)).
%o A357146 (PARI) a(n) = n!*sum(k=0, n\2, (n-2*k)^(2*k)/(n-2*k)!);
%o A357146 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(sum(k=0, N, x^k/(k!*(1-(k*x)^2)))))
%Y A357146 Cf. A354436, A357147.
%Y A357146 Cf. A353016, A356628.
%K A357146 nonn
%O A357146 0,4
%A A357146 _Seiichi Manyama_, Sep 15 2022