A065970 a(n) = n^2 * Sum_{primes p dividing n} (1 - 1/p^2).

0, 3, 8, 12, 24, 59, 48, 48, 72, 171, 120, 236, 168, 339, 416, 192, 288, 531, 360, 684, 824, 843, 528, 944, 600, 1179, 648, 1356, 840, 2339, 960, 768, 2048, 2019, 2376, 2124, 1368, 2523, 2864, 2736, 1680, 4619, 1848, 3372, 3744, 3699, 2208

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, A065969.

Sequence in context: A379717 A128303 A123906 * A326890 A024463 A092954

Adjacent sequences: A065967 A065968 A065969 * A065971 A065972 A065973

Keyword

nonn

Author

N. J. A. Sloane, Dec 09 2001

Status

approved