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A274563
Numbers k such that sigma(k) == 0 (mod k+9).
2
15, 208, 6976, 8415, 31815, 351351, 2077696, 20487159, 159030135, 536559616, 2586415095, 137433972736, 2199003332608
OFFSET
1,1
EXAMPLE
sigma(15) mod (15 + 9) = 24 mod 24 = 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
Select[Range[10^6], Mod[DivisorSigma[1, #], # + 9] == 0 &] (* Michael De Vlieger, Jul 06 2016 *)
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Jul 06 2016
EXTENSIONS
a(7)-a(13) from Giovanni Resta, Jul 06 2016
STATUS
approved