A274564 - OEIS

A274564

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

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

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OFFSET

1,1

LINKS

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

KEYWORD

nonn,more

AUTHOR

EXTENSIONS

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

STATUS

approved