A379699 Expansion of e.g.f. (1/x) * Series_Reversion( x * exp(-x) / (1 + 2*x*exp(x)) ).
1, 3, 27, 430, 10013, 309146, 11932303, 553740958, 30053978361, 1868855561938, 131048808861491, 10232894227577462, 880688476587319573, 82836081054992159194, 8454536286883278469431, 930656450818831650930766, 109910217042754940709650417, 13862746369348872200671305890
Offset: 0
Keywords
Programs
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PARI
a(n) = n!*sum(k=0, n, 2^(n-k)*(2*n-k+1)^k*binomial(n+1, n-k)/k!)/(n+1);
Formula
a(n) = (n!/(n+1)) * Sum_{k=0..n} 2^(n-k) * (2*n-k+1)^k * binomial(n+1,n-k)/k!.