OFFSET
1,2
LINKS
Neville Holmes, Integer Sequence Combinations
EXAMPLE
a(20) = 9(9+3)/2 = 54 because 9 = 2+2+5 and 20 = 2*2*5.
MATHEMATICA
spf[n_]:=Module[{c=Total[Times@@@FactorInteger[n]]}, (c(c+3))/2]; Join[ {0}, Rest[Array[spf, 60]]] (* Harvey P. Dale, Aug 16 2011 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
W. Neville Holmes, Aug 29 2002
STATUS
approved