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A176549
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Primes of the form 2*n^2+6*n+1.
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15
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37, 109, 541, 757, 1009, 1297, 1621, 2377, 6841, 7561, 8317, 9109, 11701, 12637, 15661, 16741, 19009, 23977, 25309, 28081, 34057, 38917, 40609, 42337, 44101, 47737, 51517, 55441, 57457, 59509, 65881, 70309, 72577, 82009, 84457, 99901
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OFFSET
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1,1
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COMMENTS
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Conjecture: 2^a(n)-1 is not prime; in other words, these primes are included in A054723.
2*a(n) + 7 is a square. - Vincenzo Librandi, Apr 09 2015
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 1..1000
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MATHEMATICA
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Select[Table[2 n^2 + 6 n + 1, {n, 2000}], PrimeQ] (* Vincenzo Librandi, Jul 26 2012 *)
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PROG
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(Magma) [a: n in [0..300] | IsPrime(a) where a is 2*n^2+6*n+1]; // Vincenzo Librandi, Jul 26 2012
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CROSSREFS
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Primes in A059993.
Subsequence of A093838.
Cf. Primes of the form 2*n^2+2*(2*k+3)*n+(2*k+1): this sequence (k=0), A154577 (k=2), A154592 (k=3), A154601 (k=4), A217494 (k=7), A217495 (k=10), A217496 (k=11), A217497 (k=12), A217498 (k=13), A217499 (k=16), A217500 (k=17), A217501 (k=18), A217620 (k=19), A217621 (k=21).
Sequence in context: A257117 A033215 A195316 * A118536 A003164 A304612
Adjacent sequences: A176546 A176547 A176548 * A176550 A176551 A176552
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KEYWORD
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nonn,easy
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AUTHOR
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Vincenzo Librandi, Apr 20 2010
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EXTENSIONS
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Removed an obviously incorrect part of the definition - R. J. Mathar, Apr 21 2010
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STATUS
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approved
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