A065969 a(n) = n^2 * Sum_{primes p dividing n} (1 + 1/p^2).

0, 5, 10, 20, 26, 85, 50, 80, 90, 229, 122, 340, 170, 445, 484, 320, 290, 765, 362, 916, 940, 1093, 530, 1360, 650, 1525, 810, 1780, 842, 3061, 962, 1280, 2308, 2605, 2524, 3060, 1370, 3253, 3220, 3664, 1682, 5965, 1850, 4372, 4356, 4765

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Prog

(PARI) a(n) = { my(s=0); foreach(factor(n)[, 1], p, s+=1 + 1/p^2); n^2*s } \\ Harry J. Smith, Nov 05 2009

Crossrefs

Cf. A065967, A065968, A065970.

Sequence in context: A086761 A045191 A065958 * A306775 A027884 A370532

Adjacent sequences: A065966 A065967 A065968 * A065970 A065971 A065972

Keyword

nonn

Author

N. J. A. Sloane, Dec 09 2001

Status

approved