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1, 2, 3, 1, 5, 2, 7, 1, 1, 2, 11, 1, 13, 2, 1, 1, 17, 2, 19, 1, 3, 2, 23, 1, 1, 2, 1, 1, 29, 2, 31, 1, 1, 2, 1, 1, 37, 2, 3, 1, 41, 2, 43, 1, 1, 2, 47, 1, 1, 2, 1, 1, 53, 2, 1, 1, 3, 2, 59, 1, 61, 2, 1, 1, 1, 2, 67, 1, 1, 2, 71, 1, 73, 2, 3, 1, 1, 2, 79, 1, 1, 2, 83, 1, 1
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OFFSET
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1,2
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COMMENTS
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It is conjectured that this is n iff n is 1 or a prime.
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REFERENCES
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R. K. Guy, Unsolved Problems Number Theory, A17.
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LINKS
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MATHEMATICA
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Table[n/Denominator[(Sum[m^(n - 1), {m, n - 1}] + 1)/n], {n, 10}] (* Indranil Ghosh, May 17 2017 *)
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PROG
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(PARI) a(n) = n/denominator((sum(m=1, n - 1, m^(n - 1)) + 1)/n); \\ Indranil Ghosh, May 17 2017
(Python)
from sympy import Integer
def a(n): return Integer(n)/((sum(m**(n - 1) for m in range(1, n)) + 1)/Integer(n)).denominator() # Indranil Ghosh, May 17 2017
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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