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A254010
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Numbers n such that 4n+1 and 4(n+1)+1 are primes.
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1
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3, 9, 24, 27, 48, 57, 69, 78, 87, 99, 114, 153, 168, 189, 192, 213, 219, 234, 252, 273, 303, 324, 357, 372, 387, 399, 402, 423, 468, 498, 534, 567, 573, 594, 597, 609, 618, 654, 672, 687, 699, 708, 714, 738, 759, 804, 813, 864, 882, 903, 918, 924, 948, 969, 1032, 1038, 1128, 1182, 1197, 1203, 1233, 1242, 1269, 1308, 1353
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OFFSET
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1,1
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COMMENTS
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Both n and n+1 are terms in A005098. All terms are multiples of 3.
4n+1 and 4(n+1)+1 are pairs of consecutive primes. Notice that in all cases, the numbers 4(n-1)+1 and 4(n+2)+1 are not prime as they are multiples of 3.
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LINKS
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Table of n, a(n) for n=1..65.
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MAPLE
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A254010:=n->`if`(isprime(4*n+1) and isprime(4*(n+1)+1), n, NULL): seq(A254010(n), n=1..2000); # Wesley Ivan Hurt, Apr 23 2015
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MATHEMATICA
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Select[Range[1000], PrimeQ[4 # + 1] && PrimeQ[4 (# + 1) + 1] &] (* Vincenzo Librandi, Apr 24 2015 *)
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PROG
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(MAGMA) [n: n in [0..1000] | IsPrime(4*n+1) and IsPrime(4*(n+1)+1)]; // Vincenzo Librandi, Apr 24 2015
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CROSSREFS
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Cf. A005098.
Sequence in context: A129834 A029488 A198681 * A338124 A024314 A120012
Adjacent sequences: A254007 A254008 A254009 * A254011 A254012 A254013
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KEYWORD
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nonn
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AUTHOR
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Zak Seidov, Jan 22 2015
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STATUS
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approved
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