OFFSET
1,6
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
From Robert Israel, Jan 28 2018: (Start)
If n is even, a(n) = A008472(n)-2.
If n is prime, a(n) = A008472(n)-n = 0.
Otherwise, a(n) = A008472(n). (End)
EXAMPLE
The sum of odd proper distinct prime divisors of 15 is 8=3+5.
MAPLE
seq(convert(numtheory:-factorset(n) minus {2, n}, `+`), n=1..100); # Robert Israel, Jan 28 2018
MATHEMATICA
Table[Total[Select[Most[Divisors[n]], OddQ[#]&&PrimeQ[#]&]], {n, 90}] (* Harvey P. Dale, Dec 31 2023 *)
PROG
(PARI) a(n) = sumdiv(n, d, if ((d%2) && isprime(d) && (d<n), d)); \\ Michel Marcus, Jan 28 2018
CROSSREFS
KEYWORD
AUTHOR
Mohammad K. Azarian, Mar 16 2004
STATUS
approved