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 A375654 #9 Aug 23 2024 02:12:31
%S A375654 1,1,5,19,97,641,4021,33475,272609,2559457,25926661,273419411,
%T A375654 3221437825,38674360609,506595820277,6895149870211,98785254688321,
%U A375654 1496456813264705,23400554985371269,386926938274889107,6593495476334628641,117506166655500705601
%N A375654 Expansion of e.g.f. exp(2*x^2 + x * exp(x^2)).
%F A375654 a(n) = n! * Sum_{k=0..floor(n/2)} (n-2*k+2)^k / (k! * (n-2*k)!).
%o A375654 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(2*x^2+x*exp(x^2))))
%o A375654 (PARI) a(n) = n!*sum(k=0, n\2, (n-2*k+2)^k/(k!*(n-2*k)!));
%Y A375654 Cf. A216688, A375653.
%Y A375654 Cf. A375627.
%K A375654 nonn
%O A375654 0,3
%A A375654 _Seiichi Manyama_, Aug 22 2024