OFFSET
0,4
COMMENTS
Moebius transform of A000670(n-1)=[1,1,3,13,75,...] is a(n)=[1,0,2,12,74,...]. - Michael Somos, Mar 04 2004
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..420
David Feldman, Counting plane trees, Unpublished manuscript, 1992. (Annotated scanned copy)
N. J. A. Sloane, Transforms
MATHEMATICA
a[n_] := DivisorSum[n, MoebiusMu[n/#]*(#-1)!*SeriesCoefficient[1/(2-Exp[x + O[x]^#]), #-1]&]; a[0]=0; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Dec 03 2015, adapted from PARI *)
PROG
(PARI) a(n)=if(n<1, 0, sumdiv(n, d, moebius(n/d)*(d-1)!*polcoeff(1/(2-exp(x+O(x^d))), d-1)))
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved