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A274564 Numbers k such that sigma(k) == 0 (mod k-9). 2
10, 11, 15, 19, 24, 33, 105, 33705, 33624064, 2199041081344 (list; graph; refs; listen; history; text; internal format)
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
Sequence in context: A043801 A043809 A043818 * A112787 A264719 A214792
KEYWORD
nonn,more
AUTHOR
Paolo P. Lava, Jul 06 2016
EXTENSIONS
a(9)-a(10) from Giovanni Resta, Jul 06 2016
STATUS
approved

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Last modified May 27 06:20 EDT 2024. Contains 372848 sequences. (Running on oeis4.)