A274564 Numbers k such that sigma(k) == 0 (mod k-9).

10, 11, 15, 19, 24, 33, 105, 33705, 33624064, 2199041081344

Offset

1,1

Links

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

Example

sigma(10) mod (10 - 9) = 18 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, -9);

Mathematica

k = -9; Select[Range[Abs@k+1, 10^6], Mod[DivisorSigma[1, #], # + k] == 0 &] (* Vincenzo Librandi, Jul 06 2016 *)

Prog

(Magma) [n: n in [10..2*10^6] | SumOfDivisors(n) mod (n-9) eq 0 ]; // Vincenzo Librandi, Jul 06 2016

Crossrefs

Cf. A045770, A067702, A088833, A181598, A223608, A274551-A274563, A274565, A274566.

Sequence in context: A043801 A043809 A043818 * A112787 A264719 A214792

Adjacent sequences: A274561 A274562 A274563 * A274565 A274566 A274567

Keyword

nonn,more

Author

Paolo P. Lava, Jul 06 2016

Extensions

a(9)-a(10) from Giovanni Resta, Jul 06 2016

Status

approved