A152985 Sum of proper divisors minus the number of proper divisors of the square A000290(n).

0, 1, 2, 11, 4, 47, 6, 57, 36, 109, 10, 245, 12, 195, 170, 247, 16, 509, 18, 547, 292, 439, 22, 1055, 152, 597, 358, 969, 28, 1895, 30, 1013, 632, 985, 534, 2431, 36, 1215, 850, 2317, 40, 3397, 42, 2173, 1712, 1747, 46, 4313, 396, 2953, 1382, 2955, 52, 4715, 1090, 4083

Offset

1,3

Links

B. D. Swan, Table of n, a(n) for n=1,...,50000

Formula

a(n) = A001065(A000290(n)) - A032741(A000290(n)) = A152770(A000290(n)).

Prog

(PARI) a(n) = sigma(n^2) - n^2 - (numdiv(n^2) - 1); \\ Michel Marcus, Jan 28 2014

Crossrefs

Cf. A000005, A000203, A000290, A001065, A032741, A152770.

Sequence in context: A082264 A070532 A038217 * A257112 A077272 A009301

Adjacent sequences: A152982 A152983 A152984 * A152986 A152987 A152988

Keyword

nonn,look

Author

Omar E. Pol, Dec 21 2008

Status

approved