A368292 Expansion of e.g.f. exp(x) / (1 - x*exp(3*x)).
1, 2, 11, 97, 1109, 15821, 271255, 5425967, 124032137, 3189663433, 91141189931, 2864686414547, 98226339773677, 3648723468367277, 145961603607355775, 6256040115149251591, 286015221831125756945, 13893373399551594686609, 714578347872583574806099
Offset: 0
Programs
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PARI
a(n) = n!*sum(k=0, n, (3*(n-k)+1)^k/k!);
Formula
a(n) = n! * Sum_{k=0..n} (3*(n-k)+1)^k / k!.