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A122429 Primes p such that q=4p^2+1, r=4q^2+1 and s=4r^2+1 are all primes. +0
1
13, 9833, 41647, 151607, 264757, 356123, 361223, 446863, 449093, 457813, 531383, 641057, 655927, 841697, 855947, 899263, 913687, 1052813, 1081757, 1379383, 1506493, 1575757, 1685087, 1821013, 1821377, 1981517, 2054233, 2142037 (list; graph; listen)
OFFSET

1,1

COMMENT

Next terms up to 400000th prime are 2286877, 2524157, 2595247, 2621737, 2931583, 3023437, 3425843, 3428567, 3538517, 3705187, 3777883, 3799717, 3875143, 3913727, 3973553, 4019833, 4167073, 4249523, 4488167, 4651873, 4822193, 4914937, 5054167, 5108293, 5140147, 5465303, 5520007, 5542003 [Zak Seidov (zakseidov(AT)yahoo.com), Jan 16 2009]

EXAMPLE

13 is there because 13, 677, 1833317 and 13444204889957 are primes.

MATHEMATICA

Reap[Do[p=Prime[n]; q=4p^2+1; r=4q^2+1; s=4r^2+1; If[PrimeQ[{q, r, s}]=={True, True, True}, Sow[p]], {n, 15000}]][[2, 1]]

CROSSREFS

Cf. A052291, A005574, A001912.

Sequence in context: A032463 A060887 A020521 this_sequence A068731 A098562 A123921

Adjacent sequences: A122426 A122427 A122428 this_sequence A122430 A122431 A122432

KEYWORD

nonn

AUTHOR

Zak Seidov (zakseidov(AT)yahoo.com), Oct 20 2006

EXTENSIONS

More terms from Don Reble (djr(AT)nk.ca), Oct 24 2006

Edited by R. J. Mathar, Nov 02 2009

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Last modified December 19 21:04 EST 2009. Contains 171054 sequences.


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