OFFSET
0,3
LINKS
Robert Israel, Table of n, a(n) for n = 0..500
FORMULA
MAPLE
sopf:= n -> convert(numtheory:-factorset(n), `+`):
seq(sopf(2^n-1), n=0..100); # Robert Israel, Jan 14 2021
MATHEMATICA
Table[Sum[FactorInteger[2^n - 1][[m]][[1]], {m, 1, Length[FactorInteger[2^n - 1]]}], {n, 0, 50}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Roger L. Bagula, Nov 22 2008
EXTENSIONS
Edited by N. J. A. Sloane, Nov 26 2008
STATUS
approved