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A088503
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Numbers n such that (n^2 + 3)/4 is prime.
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3
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3, 5, 7, 11, 13, 17, 25, 29, 31, 35, 41, 43, 49, 55, 67, 77, 83, 101, 109, 115, 119, 125, 133, 139, 143, 151, 155, 157, 161, 179, 181, 199, 203, 211, 221, 223, 235, 239, 263, 277, 283, 287, 295, 301, 307, 311, 323, 325, 329, 335, 337, 347, 353, 377, 379, 385
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| Under Bunyakovsky's conjecture this sequence is infinite. [Charles R Greathouse IV, Dec 28 2011]
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FORMULA
| a(n) = 2*A002384(n+1) + 1 = Sqrt(A110284(n+1)). - Ray Chandler (rayjchandler(AT)sbcglobal.net), Sep 07 2005
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EXAMPLE
| (25*25 + 3)/4 = 157, 157 is prime, 25 is the 6-th term of the sequence.
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PROG
| (PARI) for(k=2, 1e3, if(isprime(k^2+k+1), print1(2*k+1", "))) \\ Charles R Greathouse IV, Dec 28 2011
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CROSSREFS
| Cf. A002383, A002384, A110284.
Sequence in context: A154868 A020628 A108816 * A118939 A087382 A025127
Adjacent sequences: A088500 A088501 A088502 * A088504 A088505 A088506
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KEYWORD
| easy,nonn
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AUTHOR
| Pierre CAMI (colettecami(AT)aol.com), Nov 13 2003
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EXTENSIONS
| Corrected and extended by Ray Chandler (rayjchandler(AT)sbcglobal.net), Nov 16 2003
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