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A275059
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Numbers n such that A000010(n) + n^2 is a prime.
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1
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1, 2, 3, 5, 11, 13, 15, 19, 31, 33, 35, 41, 51, 53, 59, 65, 83, 89, 91, 101, 103, 115, 131, 141, 149, 161, 163, 181, 185, 187, 191, 193, 199, 217, 221, 233, 241, 263, 281, 287, 295, 303, 329, 331, 349, 373, 401, 415, 419, 431, 433, 445, 449, 461, 463, 469, 473, 499, 517
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OFFSET
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1,2
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COMMENTS
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For n >= 2, a(n) is odd and squarefree. - Robert Israel, Jul 29 2016
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LINKS
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EXAMPLE
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5 is a term because A000010(5) + 5^2 = 29 is a prime number.
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MAPLE
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select(t -> isprime(numtheory:-phi(t) + t^2), [1, 2, seq(n, n=3..1000, 2)]); # Robert Israel, Jul 29 2016
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MATHEMATICA
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Select[Range[2000], PrimeQ[#^2 + EulerPhi[#]] &]
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PROG
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(Magma) [n: n in [1..800] | IsPrime(n^2+EulerPhi(n))];
(PARI) isok(n) = isprime(eulerphi(n) + n^2); \\ Altug Alkan, Jul 27 2016
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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