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 A370668 #10 Feb 25 2024 04:28:32
%S A370668 1,3,6,28,120,740,5040,40416,362898,3629400,39916800,479006070,
%T A370668 6227020800,87178326480,1307674369200,20922790210656,355687428096000,
%U A370668 6402373709004720,121645100408832000,2432902008212929224,51090942171709545840,1124000727778046764800
%N A370668 Expansion of Sum_{k>0} k! * ( x * (1+x^k) )^k.
%F A370668 a(n) = Sum_{d|n} d! * binomial(d,n/d-1).
%F A370668 If p is an odd prime, a(p) = p!.
%o A370668 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=1, N, k!*(x*(1+x^k))^k))
%o A370668 (PARI) a(n) = sumdiv(n,d, d!*binomial(d, n/d-1));
%Y A370668 Cf. A240172, A370509, A370510.
%Y A370668 Cf. A217668.
%K A370668 nonn
%O A370668 1,2
%A A370668 _Seiichi Manyama_, Feb 25 2024