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A260678
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Numbers n>0 for which n+(17-n)^2 is not prime.
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2
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33, 34, 37, 42, 49, 50, 51, 53, 56, 58, 60, 65, 67, 68, 69, 71, 72, 75, 78, 82, 83, 84, 85, 86, 88, 91, 94, 95, 97, 100, 101, 102, 105, 106, 107, 110, 111, 113, 114, 116, 117, 118, 119, 122, 123, 124, 128, 129, 132, 133, 134, 135, 136, 139, 141, 143, 148, 151, 152, 153
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OFFSET
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1,1
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COMMENTS
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Motivated by the fact that n+(17-n)^2 = 1+16^2, 2+15^2, ..., 16+1^2, 17+0^2, 18+1^2, 19+2^2, ..., 32+15^2 are all prime. This has an explanation through Heegener numbers, similar to Euler's prime-generating polynomial, cf. A002837 and related crossrefs.
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LINKS
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MAPLE
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remove(t -> isprime(t+(17-t)^2), [$1..200]); # Robert Israel, May 02 2017
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MATHEMATICA
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PROG
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(PARI) for(n=1, 999, isprime(n+(17-n)^2)||print1(n", "))
(Magma) [n: n in [1..180] | not IsPrime(n+(17-n)^2)]; // Vincenzo Librandi, Nov 16 2015
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CROSSREFS
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Cf. A260679 (n+(17-n)^2), A007635 (primes in that sequence = primes of the form n^2+n+17).
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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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