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 A057327 First member of a prime quadruple in a 2p-1 progression. 10
 1531, 2131, 2311, 3061, 6211, 6841, 7411, 10321, 13681, 15391, 16651, 18121, 22531, 23011, 24391, 29671, 30781, 31771, 33301, 35311, 41491, 44371, 46411, 54601, 56311, 57991, 60331, 61381, 66601, 67651, 78031, 83431, 85381, 88741 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Numbers n such that n remains prime through 3 iterations of function f(x) = 2x - 1. LINKS Harvey P. Dale, Table of n, a(n) for n = 0..1000 EXAMPLE Quadruplets are (1531,3061,6121,12241),(2131,4261,8521,17041),... MATHEMATICA Select[Prime[Range[9000]], And@@PrimeQ[NestList[2#-1&, #, 3]]&] (* Harvey P. Dale, May 27 2012 *) CROSSREFS Cf. (A005382 and A005383), A057326, A057328, A057329, A057330, A005603. Sequence in context: A031717 A030061 A122707 * A057328 A110022 A145982 Adjacent sequences:  A057324 A057325 A057326 * A057328 A057329 A057330 KEYWORD nonn AUTHOR Patrick De Geest, Aug 15 2000. STATUS approved

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