A058076 Numbers k such that k | sigma_3(k) + sigma_2(k) + sigma_1(k) + sigma_0(k).

1, 4, 5, 6, 9, 14, 42, 69, 138, 428, 2772, 3243, 3306, 4830, 7882, 24720, 49710, 53403, 314184, 1351280, 1847772, 27247596, 31525032, 41113416, 41590824, 42844894, 44193564, 47287104, 95962560, 104935384, 124365885, 211756464, 569983507, 615634082, 824808026, 1282142278

Offset

1,2

Links

Table of n, a(n) for n=1..36.

Mathematica

Do[ If[ Mod[ DivisorSigma[3, n] + DivisorSigma[2, n] + DivisorSigma[1, n] + DivisorSigma[0, n], n] == 0, Print[n]], {n, 1, 6.6 10^6}]

Prog

(PARI) isok(k) = {my(f = factor(k)); !(sum(i = 0, 3, sigma(f, i)) % k); } \\ Amiram Eldar, Feb 16 2026

Crossrefs

Cf. A000005 (sigma_0), A000203 (sigma_1), A001157 (sigma_2), A001158 (sigma_3).

Sequence in context: A241511 A020669 A091730 * A238712 A033819 A058782

Adjacent sequences: A058073 A058074 A058075 * A058077 A058078 A058079

Keyword

nonn

Author

Robert G. Wilson v, Nov 11 2000

Extensions

a(22)-a(33) from Donovan Johnson, Mar 06 2011

a(34)-a(36) from Amiram Eldar, Feb 16 2026

Status

approved