A379690 Expansion of e.g.f. (1/x) * Series_Reversion( x * (1 - x*exp(2*x)) ).
1, 1, 8, 102, 1952, 49920, 1603392, 62100304, 2818386944, 146748098304, 8624885719040, 564885716972544, 40800979548180480, 3222148806557544448, 276214603877715378176, 25544721442331112192000, 2535168741071076287971328, 268757182971129822376624128, 30311086789573678207758237696
Offset: 0
Keywords
Programs
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PARI
a(n) = sum(k=0, n, (2*n-2*k)^k * (2*n-k)!/(k!*(n-k)!))/(n+1);
Formula
a(n) = (1/(n+1)) * Sum_{k=0..n} (2*n-2*k)^k * (2*n-k)!/(k! * (n-k)!).