OFFSET
1,3
FORMULA
p divides a(p^k) for prime p and integer k>1. p divides a(p), a(2p) and a(2p^2) for prime p>2. - Alexander Adamchuk, Jul 27 2006
MATHEMATICA
f[n_] := Block[{s = 0, d = 1}, While[d < n, If[ Mod[n, d] != 0, s = s + n/d]; d++ ]; s]; Numerator[ Table[ f[n], {n, 1, 28}]]
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Reinhard Zumkeller, Dec 21 2002
EXTENSIONS
Edited and extended by Robert G. Wilson v, Dec 30 2002
STATUS
approved