A274560 Numbers k such that sigma(k) == 0 (mod k-7).

8, 10, 11, 15, 27, 34, 72, 232, 34432, 549762629632

Offset

1,1

Links

Table of n, a(n) for n=1..10.

Example

sigma(8) mod (8-7) = 15 mod 1 = 0.

Maple

with(numtheory); P:=proc(q, h) local n;  for n from 1 to q do
if n+h>0 then if type(sigma(n)/(n+h), integer) then print(n); fi; fi; od; end: P(10^9, -7);

Mathematica

Select[Range[8, 10^6], Mod[DivisorSigma[1, #], # - 7] == 0 &] (* Michael De Vlieger, Jul 05 2016 *)

Crossrefs

Cf. A000203, A045770, A067702, A088833, A181598, A274551-A274559, A274561-A274566.

Sequence in context: A265200 A126803 A256385 * A122990 A288107 A062372

Adjacent sequences: A274557 A274558 A274559 * A274561 A274562 A274563

Keyword

nonn,more

Author

Paolo P. Lava, Jul 05 2016

Extensions

a(10) from Giovanni Resta

Status

approved