OFFSET
1,2
LINKS
G. C. Greubel, Table of n, a(n) for n = 1..450
FORMULA
E.g.f.: Sum_{k>0} (exp(x^k)-1)/k = -Sum_{k>0} log(1-x^k)/k!.
MATHEMATICA
Array[n \[Function] DivisorSum[n, (n - 1)!/(# - 1)! &], 25] (* J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010 *)
PROG
(PARI) a(n)=sumdiv(n, d, (n-1)!/(d-1)!); \\ Joerg Arndt, May 21 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Vladeta Jovovic, Oct 15 2003
EXTENSIONS
More terms from J. Mulder (jasper.mulder(AT)planet.nl), Jan 25 2010
STATUS
approved