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 A076901 #12 Sep 14 2017 08:35:53
%S A076901 1,1,1,4,21,96,520,3795,32053,284368,2763876,30648465,373339824,
%T A076901 4833294389,67167087793,1009753574739,16215467043493,275361718915824,
%U A076901 4947532173402532,94054153646919213,1882793796608183356,39528099512321898363,869222284280777733043
%N A076901 E.g.f.: 1/Product_{m>0} (1+(-x)^m/m!).
%H A076901 Seiichi Manyama, <a href="/A076901/b076901.txt">Table of n, a(n) for n = 0..200</a>
%F A076901 a(n) ~ c * n!, where c = Product_{k>=2} (1 + (-1)^k/k!) = 0.773515873861910082... - _Vaclav Kotesovec_, Sep 14 2017
%p A076901 A076901 := proc(n) local a, s;
%p A076901 s := proc(n) local d; add((-1)^d*n!/(d*(n/d)!^d),
%p A076901 d = numtheory[divisors](n)) end:
%p A076901 a := proc(n) option remember; local k;
%p A076901 `if`(n=0, 1, add(binomial(n-1,k-1)*s(k)*a(n-k),k = 1..n)) end:
%p A076901 (-1)^n*a(n) end:
%p A076901 seq(A076901(n), n=0..20); # _Peter Luschny_, Apr 16 2011
%t A076901 nmax = 25; Table[SeriesCoefficient[Product[1/(1 + (-x)^k/k!), {k, 1, n}], {x, 0, n}], {n, 0, nmax}] * Range[0, nmax]! (* _Vaclav Kotesovec_, Sep 14 2017 *)
%Y A076901 Cf. A005651, A182928.
%K A076901 nonn
%O A076901 0,4
%A A076901 _Vladeta Jovovic_, Nov 26 2002