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A274560
Numbers k such that sigma(k) == 0 (mod k-7).
2
8, 10, 11, 15, 27, 34, 72, 232, 34432, 549762629632
OFFSET
1,1
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 *)
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Jul 05 2016
EXTENSIONS
a(10) from Giovanni Resta
STATUS
approved