A033882 Abundancy of the abundant or perfect numbers: m = sigma(k)-2k for n such that m >= 0.

0, 4, 3, 2, 12, 0, 12, 19, 10, 12, 28, 12, 8, 48, 12, 4, 51, 12, 26, 56, 4, 54, 60, 17, 12, 2, 64, 24, 12, 120, 60, 72, 12, 56, 115, 72, 80, 58, 39, 144, 12, 20, 186, 12, 124, 7, 72, 65, 96, 18, 156, 168, 64, 12, 56, 104

Offset

1,2

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n) = A033880(A023196(n)). - Amiram Eldar, Apr 06 2024

Mathematica

Select[Table[DivisorSigma[1, n]-2n, {n, 250}], #>=0&] (* Harvey P. Dale, Jan 22 2015 *)

Prog

(PARI) lista(kmax) = {my(ab); for(k = 1, kmax, ab = sigma(k)-2*k; if(ab >= 0, print1(ab, ", "))); } \\ Amiram Eldar, Apr 06 2024

Crossrefs

Cf. A000203, A023196, A033880.

Sequence in context: A227182 A065367 A333780 * A062111 A181596 A182142

Adjacent sequences: A033879 A033880 A033881 * A033883 A033884 A033885

Keyword

nonn

Author

N. J. A. Sloane

Extensions

Offset corrected by Amiram Eldar, Apr 06 2024

Status

approved