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A274558
Numbers k such that sigma(k) == 0 (mod k-6).
2
7, 13, 14, 20, 30, 45, 76, 630, 688, 2310, 8896, 133888, 537051136, 1631268870
OFFSET
1,1
EXAMPLE
sigma(7) mod (7-6) = 8 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, -6);
MATHEMATICA
Select[Range[7, 10^6], Mod[DivisorSigma[1, #], # - 6] == 0 &] (* Michael De Vlieger, Jul 05 2016 *)
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Jul 05 2016
EXTENSIONS
a(13)-a(14) from Giovanni Resta
STATUS
approved