OFFSET
1,2
LINKS
R. J. Mathar, Table of n, a(n) for n = 1..10000
Eric Weisstein's World of Mathematics, Prime Power.
Eric Weisstein's World of Mathematics, Divisor Function
MAPLE
MATHEMATICA
DivisorSigma[1, #]& /@ Join[{1}, Select[Range[2, 200], PrimePowerQ]] (* Jean-François Alcover, Feb 10 2018 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Jul 20 2003
STATUS
approved