OFFSET
1,4
COMMENTS
a(n) is the total number of prime factors (counted with multiplicity) over all the divisors of n. - Geoffrey Critzer, Feb 03 2015
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..10000
FORMULA
a(n) = tau(n)*bigomega(n)/2. - Vladeta Jovovic, Jan 25 2004
G.f.: Sum_{k>=1} bigomega(k)*x^k/(1 - x^k). - Ilya Gutkovskiy, Feb 19 2017
EXAMPLE
a(12)=9 because the divisors of 12 are: 1,2,3,4,6,12 and the number (with multiplicity) of prime factors of these divisors is: 0+1+1+2+2+3=9. - Geoffrey Critzer, Feb 03 2015
MATHEMATICA
Table[Sum[PrimeOmega[d], {d, Divisors[n]}], {n, 1, 94}] (* Geoffrey Critzer, Feb 03 2015 *)
PROG
(PARI) for(n=1, 120, print1(sumdiv(n, d, bigomega(d)), ", "))
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Benoit Cloitre, Apr 19 2002
STATUS
approved