OFFSET
1,1
COMMENTS
Factorizations : 2*3, 2^2*7, 2^5*3*47, 2^4*3^2*5*7*13, 2^7*5^2*7*31
No other terms < 3000000000. - Jud McCranie, Jul 16 2004
EXAMPLE
01PPsigma(2^5*3^3)=(1+2+2^2+2^3+2^5)*(1+3+3^2+3^3)=1880
All exponents of the terms are 0 or 1 or prime.
CROSSREFS
KEYWORD
nonn
AUTHOR
Yasutoshi Kohmoto, Jul 08 2004
STATUS
approved