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Search: id:A164041
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| A164041 |
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Primes of the form 2*p^2+4*p+1, where p is also prime. |
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+0
2
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| 17, 31, 71, 127, 647, 1151, 2887, 3527, 7687, 12799, 19207, 20807, 23327, 34847, 39199, 49927, 53791, 73727, 79999, 103967, 117127, 145799, 172871, 194687, 220447, 279751, 294911, 323207, 336199, 387199, 394271, 419527, 438047, 587527, 649799, 724807
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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A subsequence of the primes of the form 2k^2+4k+1 = 2*(k+1)^2-1, A066436. - R. J. Mathar, Aug 10 2009
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FORMULA
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a(n) = 2*(A164042(n))^2+4*A164042(n)+1.
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MATHEMATICA
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lst={}; Do[p=Prime@n; a=2*p^2+4*p+1; If[PrimeQ@a, AppendTo[lst, a]], {n, 7!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Aug 12 2009]
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CROSSREFS
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Sequence in context: A134076 A160961 A167496 this_sequence A085598 A163443 A027722
Adjacent sequences: A164038 A164039 A164040 this_sequence A164042 A164043 A164044
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KEYWORD
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nonn
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AUTHOR
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Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 08 2009
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EXTENSIONS
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a(29) corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 11 2009
Edited by N. J. A. Sloane, Aug 11 2009
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