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A199167
Smallest number k such that the sum of the n-th powers of the divisors of k is divisible by n.
2
1, 3, 2, 15, 8, 12, 4, 105, 2, 3, 43, 60, 9, 12, 8, 945, 67, 300, 37, 240, 5, 48, 137, 420, 8, 5, 2, 60, 173, 12, 16, 10395, 86, 13, 76, 2100, 73, 147, 8, 1680, 163, 4800, 257, 240, 8, 3072, 281, 3780, 4, 3, 101, 60, 211, 14700, 8, 420, 32, 17, 353, 8400, 169
OFFSET
1,2
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..200
EXAMPLE
a(6) = 12 because the divisors of 12 are 1, 2, 3, 4, 6, 12 and 1^6 + 2^6 + 3^6 + 4^6 + 6^6 + 12^6 = 3037530 = 6*506255.
MAPLE
with(numtheory):
a:= proc(n) local k;
for k while irem (add (d &^n mod n, d=divisors(k)), n)<>0
do od; k
end:
seq (a(n), n=1..63);
MATHEMATICA
snk[n_]:=Module[{k=1}, While[!Divisible[DivisorSigma[n, k], n], k++]; k]; Array[ snk, 70] (* Harvey P. Dale, Jun 07 2016 *)
PROG
(PARI) a(n)=my(k); while(sigma(k++, n)%n, ); k \\ Charles R Greathouse IV, Nov 03 2011
CROSSREFS
Cf. A066135.
Sequence in context: A334865 A103236 A141235 * A218969 A345291 A185973
KEYWORD
nonn
AUTHOR
Michel Lagneau, Nov 03 2011
STATUS
approved