A335153 a(1)=0; thereafter a(n) = (n-1)*sigma(n)-n*sigma(n-1) where sigma is the sum-of-divisors function A000203.

0, 1, -1, 5, -11, 24, -36, 41, -31, 32, -78, 164, -196, 116, -24, 81, -239, 339, -381, 398, -242, 52, -300, 804, -756, 244, -94, 392, -784, 1188, -1272, 929, -543, 150, -258, 1457, -1999, 776, -212, 1270, -2010, 2172, -2280, 1676, -348, -348, -1176, 3524, -3340, 1707, -1143, 1254, -2386, 3444, -2712, 2568, -2360, 490

Offset

1,4

Links

N. J. A. Sloane, Table of n, a(n) for n = 1..10000

Mathematica

Join[{0}, Table[(n-1)DivisorSigma[1, n]-n DivisorSigma[1, n-1], {n, 2, 60}]] (* Harvey P. Dale, Dec 30 2021 *)

Crossrefs

Sequence in context: A065114 A309730 A102171 * A122926 A122925 A021008

Adjacent sequences: A335150 A335151 A335152 * A335154 A335155 A335156

Keyword

sign

Author

N. J. A. Sloane, May 30 2020

Status

approved