OFFSET
1,4
COMMENTS
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
FORMULA
G.f.: Sum_{n > 0} A000041(n)*x^(2*n)/(1-x^n). - Mircea Merca, Feb 24 2014
G.f.: x^2 + x^3 + 3*x^4 + x^5 + 6*x^6 + x^7 + 8*x^8 + 4*x^9 + 10*x^10 + x^11 + ... - Michael Somos, Feb 24 2014
MAPLE
MATHEMATICA
a[ n_] := If[n < 1, 0, Sum[ PartitionsP[ d] Boole[ d < n], {d, Divisors @ n}]]; (* Michael Somos, Feb 24 2014 *)
PROG
(PARI) A168111(n) = sumdiv(n, d, (d<n)*numbpart(d)); \\ Antti Karttunen, Nov 14 2017
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Omar E. Pol, Nov 22 2009
EXTENSIONS
Terms beyond a(12) from R. J. Mathar, Jan 25 2010
New name from Omar E. Pol, Feb 25 2014
STATUS
approved