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A180341
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a(n) = k is the smallest number such that n is the number of distinct primes dividing k^k + 1.
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0
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0, 3, 5, 9, 13, 11, 18, 23, 40, 30, 27, 60, 35, 45, 91, 69, 98, 63, 119
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OFFSET
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1,2
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LINKS
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EXAMPLE
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a(6) = 11 because the 6 distinct primes dividing 11^11 + 1 = 285311670612 are
{2, 3, 23, 89, 199, 58367}.
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MAPLE
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with(numtheory):for n from 1 to 8 do:ind:=0:for k from 1 to 40 while(ind=0)
do: x:=k^k+1:y:=nops(factorset(x)):if y=n then ind:=1:printf(`%d, `, k):else
fi:od: od:
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CROSSREFS
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KEYWORD
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nonn,hard
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AUTHOR
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STATUS
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approved
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