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A096012
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Numbers k such that k^2+1 and (k+2)^2+1 are both prime; twin k^2+1 primes.
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12
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2, 4, 14, 24, 54, 124, 204, 384, 464, 634, 644, 714, 1094, 1144, 1174, 1244, 1274, 1314, 1374, 1564, 1614, 1674, 1684, 1964, 2054, 2084, 2094, 2404, 2454, 2534, 2664, 2834, 2924, 3134, 3304, 3534, 3754, 3774, 4024, 4154, 4174, 4364, 4604, 4614, 4734, 4784
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OFFSET
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1,1
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LINKS
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Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..1000 from Seiichi Manyama)
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FORMULA
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a(k) = A108814(k) - 1. - Jeppe Stig Nielsen, Feb 26 2016
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MATHEMATICA
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Select[Range[5000], AllTrue[{#^2+1, (#+2)^2+1}, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Jul 23 2014 *)
Select[Range[5000], PrimeQ[#^2 + 1] && PrimeQ[(# + 2)^2 + 1] &] (* Vincenzo Librandi, Feb 27 2016 *)
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PROG
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(MAGMA) [n: n in [1..5000] | IsPrime(n^2+1) and IsPrime((n+2)^2+1)]; // Vincenzo Librandi, Feb 27 2016
(PARI) isok(n) = isprime(n^2+1) && isprime((n+2)^2+1); \\ Michel Marcus, Feb 27 2016
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CROSSREFS
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Cf. A005574, A108814.
Sequence in context: A283290 A283379 A090889 * A261562 A102930 A135113
Adjacent sequences: A096009 A096010 A096011 * A096013 A096014 A096015
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KEYWORD
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easy,nonn
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AUTHOR
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Jason Earls, Jul 20 2004
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STATUS
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approved
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