login
Expansion of e.g.f. exp(-1 + Product_{k>=1} (1 + x^k/k)).
3

%I #5 May 21 2019 02:48:10

%S 1,1,2,9,44,270,2064,17682,171296,1867968,22470840,294493320,

%T 4195969392,64416698112,1059685905264,18609306423120,347179119075840,

%U 6855335163907200,142889687354283264,3133647091691585280,72124075333003155840,1738384773846440146560

%N Expansion of e.g.f. exp(-1 + Product_{k>=1} (1 + x^k/k)).

%F a(0) = 1; a(n) = Sum_{k=1..n} binomial(n-1,k-1)*A007838(k)*a(n-k).

%t nmax = 21; CoefficientList[Series[Exp[Product[(1 + x^k/k), {k, 1, nmax}] - 1], {x, 0, nmax}], x] Range[0, nmax]!

%Y Cf. A007838, A308336, A308337.

%K nonn

%O 0,3

%A _Ilya Gutkovskiy_, May 20 2019