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 A141004 E.g.f. exp(sum_{d|M} (exp(d*x)-1)/d), M=6. 6
 1, 4, 28, 258, 2892, 37778, 560124, 9256010, 168182044, 3325057826, 70934634236, 1621828212826, 39517131361884, 1021237022557682, 27877344103738940, 800976143703407210, 24148078430008534428 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 0..200 MATHEMATICA u[0, j_]:=1; u[k_, j_]:=u[k, j]=Sum[Binomial[k-1, i-1]Plus@@(u[k-i, j]#^(i-1)&/@Divisors[j]), {i, k}]; Table[u[n, 6], {n, 0, 12}] [From Wouter Meeussen, Dec 06 2008] CROSSREFS u[n,j] generates for j=1, A000110 Bell numbers; j=2, A002872 "Sorting numbers"; j=3, A002874 "Sorting numbers"; j=4, A141003 (Mathar); j=5, A036075 "Sorting numbers"; j=6, A141004 (Mathar); j=7, A036077 "Sorting numbers" [From Wouter Meeussen, Dec 06 2008] Column k=6 of A162663. Sequence in context: A064340 A002895 A294189 * A217806 A152410 A177403 Adjacent sequences:  A141001 A141002 A141003 * A141005 A141006 A141007 KEYWORD nonn AUTHOR R. J. Mathar, Jul 11 2008 STATUS approved

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Last modified January 22 10:32 EST 2019. Contains 319363 sequences. (Running on oeis4.)