A274559 Numbers k such that sigma(k) == 0 (mod k+7).

8, 272, 7232, 30848, 516608, 134094848, 2146992128

Offset

1,1

Links

Table of n, a(n) for n=1..7.

Example

sigma(8) mod (8+7) = 15 mod 15 = 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[10^6], Mod[DivisorSigma[1, #], # + 7] == 0 &] (* Michael De Vlieger, Jul 05 2016 *)

Crossrefs

Cf. A141546, A045770, A067702, A088833, A181598, A274551-A274558, A274560-A274566.

Sequence in context: A300047 A336214 A129424 * A338636 A335586 A159496

Adjacent sequences: A274556 A274557 A274558 * A274560 A274561 A274562

Keyword

nonn,more

Author

Paolo P. Lava, Jul 05 2016

Extensions

a(6)-a(7) from Giovanni Resta, Jul 05 2016

Status

approved