A367308 a(0) = 1; thereafter a(n) = n*Sum_{k=0..n-1} binomial(n,k) * a(k).
1, 1, 6, 66, 1220, 34130, 1346982, 71335236, 4883183496, 419708936862, 44256845856410, 5618131203742376, 845200046197677612, 148704124317985161666, 30252055409619038022510, 7046807010054413604547740, 1863423940527969873383134736, 555177557057715635856129878246
Offset: 0
Keywords
Crossrefs
Cf. A365863.
Programs
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Mathematica
a[n_] := a[n] = If[n==0, 1, n*Sum[Binomial[n, k]*a[k], {k, 0, n-1}]]; Table[a[n], {n, 0, 20}]
Formula
a(n) ~ c * n^(2*n + 3/2) / exp(2*n), where c = 6.702694897473369225159542571434998226159280485652114977020519335049605...