A156943 Odd abundant numbers not divisible by 25 whose abundancy is odd.

81162081, 138791961, 173369889, 441882441, 730458729, 1091179089, 1249127649, 1524043521, 1560329001, 1744649361, 2286465489, 2606204601, 3255501249, 3976941969, 4770526761, 5567099769, 6574128561, 6800806089, 7584145569

Offset: 1

Author

Robert G. Wilson v, Feb 18 2009

Keywords

• nonn

Comments

Number of terms < 10^n: 0, 0, 0, 0, 0, 0, 0, 1, 5, 25, 63, ..., .

Links

• Robert G. Wilson v, Table of n, a(n) for n=1..1005

Crossrefs

Subsequence of A156903 and A156942.

Programs

Mathematica

q[n_] := Module[{ab = DivisorSigma[1, n] - 2*n}, ab > 0 && OddQ[ab]]; Select[Range[1, 7775536039, 2], ! Divisible[#, 25] && q[#] &] (* corrected by Amiram Eldar, Oct 10 2023 *)

Extensions

Name corrected by Amiram Eldar, Oct 10 2023