A274561 Numbers k such that sigma(k) == 0 (mod k+8).

10, 49, 240, 550, 748, 1504, 3192, 7192, 7912, 10792, 17272, 30592, 979992, 1713592, 4526272, 8353792, 9928792, 11547352, 17999992, 89283592, 173482552, 361702144, 1081850752, 1845991216, 2146926592, 11097907192, 12985220152, 21818579968, 34357510144, 109170719992, 228354264064, 279632332792, 549746900992, 1511712719992, 2169800814592

Offset

1,1

Links

Max Alekseyev, Table of n, a(n) for n = 1..50

Example

sigma(10) mod (10 + 8) = 18 mod 18 = 0.

Mathematica

Select[Range[10^6], Mod[DivisorSigma[1, #], # + 8] == 0 &] (* Michael De Vlieger, Jul 05 2016 *)

Prog

(PARI) isok(k) = sigma(k) % (k+8) == 0; \\ Michel Marcus, Oct 14 2025

Crossrefs

Contains subsequences: A141547 and 2 times odd terms of A088833.

Cf. A000203, A045770, A067702, A181598, A274551-A274560, A274562-A274566.

Sequence in context: A271662 A244864 A051947 * A253221 A394242 A222633

Adjacent sequences: A274558 A274559 A274560 * A274562 A274563 A274564

Keyword

nonn

Author

Paolo P. Lava, Jul 05 2016

Extensions

a(16)-a(35) from Giovanni Resta, Jul 05 2016

Status

approved