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A128981
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Numbers k such that k divides Sum_{j=1..k} j^j = A001923(k).
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7
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1, 4, 17, 19, 148, 1577, 3564, 4388, 5873, 6639, 8579, 62500, 376636, 792949, 996044, 1174065, 3333551, 5179004, 7516003
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OFFSET
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1,2
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COMMENTS
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LINKS
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MAPLE
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a:=0:
for n from 1 to 2000 do
a:=a+n^n:
if a mod n=0 then
print(n);
fi;
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MATHEMATICA
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f=0; Do[ f=f+k^k; If[ IntegerQ[f/k], Print[k] ], {k, 1, 6639} ]
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PROG
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(PARI) for(n=1, 10^4, s=sum(i=1, n, Mod(i, n)^i); if(!Mod(s, n), print1(n, ", "))) \\ Derek Orr, Jun 18 2015
(Python)
from itertools import accumulate, count, islice
def A128981_gen(): # generator of terms
yield 1
for i, j in enumerate(accumulate(k**k for k in count(1)), start=2):
if j % i == 0:
yield i
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CROSSREFS
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KEYWORD
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hard,more,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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