A327669 Sum of divisors of n that have an odd number of distinct prime factors.
0, 2, 3, 6, 5, 5, 7, 14, 12, 7, 11, 9, 13, 9, 8, 30, 17, 14, 19, 11, 10, 13, 23, 17, 30, 15, 39, 13, 29, 40, 31, 62, 14, 19, 12, 18, 37, 21, 16, 19, 41, 54, 43, 17, 17, 25, 47, 33, 56, 32, 20, 19, 53, 41, 16, 21, 22, 31, 59, 104, 61, 33, 19, 126, 18, 82, 67, 23, 26, 84
Offset: 1
Keywords
Links
- Alois P. Heinz, Table of n, a(n) for n = 1..20000
Programs
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Maple
with(numtheory): a:= n-> add(`if`(nops(factorset(d))::odd, d, 0), d=divisors(n)): seq(a(n), n=1..80); # Alois P. Heinz, Sep 21 2019
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Mathematica
a[n_] := DivisorSum[n, # &, OddQ[PrimeNu[#]] &]; Table[a[n], {n, 1, 70}]