A379691 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-x) * (1 - x*exp(2*x)) ).
1, 2, 17, 274, 6597, 212736, 8624581, 421843472, 24185705417, 1591194859264, 118184516071641, 9782950785024000, 893132377427288653, 89156432069922504704, 9661304014254414999821, 1129505503357457643206656, 141711496280128816909982097, 18992404410135723679211716608
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, (3*n-2*k+1)^k * (2*n-k)!/(k!*(n-k)!))/(n+1);
Formula
a(n) = (1/(n+1)) * Sum_{k=0..n} (3*n-2*k+1)^k * (2*n-k)!/(k! * (n-k)!).