A371235 E.g.f. satisfies A(x) = 1 - x^2*A(x)^5*log(1 - x*A(x)^2).
1, 0, 0, 6, 12, 40, 5220, 41328, 339360, 28477440, 489877920, 7325176320, 501467630400, 14323336634880, 333439476289920, 21001701037363200, 849627551212876800, 27872303353627299840, 1742879646852427791360, 90170933394707691724800
Offset: 0
Keywords
Programs
-
PARI
a(n) = n!*sum(k=0, n\3, (2*n+k)!*abs(stirling(n-2*k, k, 1))/(n-2*k)!)/(2*n+1)!;
Formula
a(n) = (n!/(2*n+1)!) * Sum_{k=0..floor(n/3)} (2*n+k)! * |Stirling1(n-2*k,k)|/(n-2*k)!.