OFFSET
1,8
COMMENTS
Omega = A001222 is the number of prime divisors of the argument, counted with multiplicity.
a(1) = 0 by convention.
LINKS
FORMULA
EXAMPLE
a(8) = 4 because Omega(8) = 3 and the sum of the 2 odd divisors {1, 3} is 4.
MATHEMATICA
Table[Total[Select[Divisors[PrimeOmega[n]], OddQ[ # ]&]], {n, 58}]
PROG
(PARI)
A000593(n) = sigma(n>>valuation(n, 2)); \\ This function from Charles R Greathouse IV, Sep 09 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Michel Lagneau, Jul 29 2011
EXTENSIONS
Description clarified, more terms from Antti Karttunen, Jul 23 2017
STATUS
approved