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A188776
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Numbers n such that Sum_{k=1..n} k^k == 1 (mod n).
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4
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OFFSET
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1,2
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COMMENTS
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Numbers n such that A001923(n) == 1 (mod n).
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LINKS
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MATHEMATICA
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Union@Table[If[Mod[Sum[PowerMod[i, i, n], {i, 1, n}], n]==1, Print[n]; n], {n, 1, 20000}]
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PROG
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(PARI)
f(n)=lift(sum(k=1, n, Mod(k, n)^k));
for(n=1, 10^6, if(f(n)==1, print1(n, ", "))) /* Joerg Arndt, Apr 10 2011 */
(Python)
from itertools import accumulate, count, islice
def A188776_gen(): # generator of terms
yield 1
for i, j in enumerate(accumulate(k**k for k in count(2)), start=2):
if not j % i:
yield i
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CROSSREFS
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KEYWORD
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nonn,more
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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