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A319697 Sum of even squarefree divisors of n. 4
0, 2, 0, 2, 0, 8, 0, 2, 0, 12, 0, 8, 0, 16, 0, 2, 0, 8, 0, 12, 0, 24, 0, 8, 0, 28, 0, 16, 0, 48, 0, 2, 0, 36, 0, 8, 0, 40, 0, 12, 0, 64, 0, 24, 0, 48, 0, 8, 0, 12, 0, 28, 0, 8, 0, 16, 0, 60, 0, 48, 0, 64, 0, 2, 0, 96, 0, 36, 0, 96, 0, 8, 0, 76, 0, 40, 0, 112, 0, 12, 0, 84, 0, 64, 0, 88, 0, 24, 0, 48, 0, 48, 0, 96 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..20000

FORMULA

a(n) = Sum_{d|n} A059841(d)*A008966(d)*d.

a(n) = A048250(n) - A206787(n).

MATHEMATICA

Table[Total[Select[Divisors[n], EvenQ[#]&&SquareFreeQ[#]&]], {n, 100}] (* Harvey P. Dale, May 18 2019 *)

PROG

(PARI) A319697(n) = sumdiv(n, d, (!(d%2))*issquarefree(d)*d);

CROSSREFS

Cf. A048250, A146076, A183063, A206787, A319698.

Sequence in context: A047765 A068463 A099554 * A107729 A300073 A113400

Adjacent sequences:  A319694 A319695 A319696 * A319698 A319699 A319700

KEYWORD

nonn

AUTHOR

Antti Karttunen, Oct 31 2018

STATUS

approved

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Last modified December 9 17:18 EST 2019. Contains 329879 sequences. (Running on oeis4.)