

A091921


Sum of odd proper distinct prime divisors of n. That is, the sum of odd distinct prime divisors of n that are less than n.


1



0, 0, 0, 0, 0, 3, 0, 0, 3, 5, 0, 3, 0, 7, 8, 0, 0, 3, 0, 5, 10, 11, 0, 3, 5, 13, 3, 7, 0, 8, 0, 0, 14, 17, 12, 3, 0, 19, 16, 5, 0, 10, 0, 11, 8, 23, 0, 3, 7, 5, 20, 13, 0, 3, 16, 7, 22, 29, 0, 8, 0, 31, 10, 0, 18, 14, 0, 17, 26, 12, 0, 3, 0, 37, 8, 19, 18, 16, 0, 5, 3, 41, 0, 10, 22, 43, 32, 11, 0
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OFFSET

1,6


LINKS



FORMULA

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



STATUS

approved



