id:A023330 - OEIS Search Results

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Numbers n such that n remains prime through 5 iterations of function f(x) = 2x + 1.

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89, 63419, 127139, 405269, 810809, 1069199, 1122659, 1178609, 1333889, 1598699, 1806089, 1958249, 2164229, 2245319, 2329469, 2606069, 2848949, 3241289, 3339989, 3784199, 3962039, 4088879, 4328459, 4444829, 4658939, 4664249, 4894889, 4897709 (list; graph; listen)

	OFFSET	`1,1`
	MATHEMATICA	`Select[Prime[Range[10^5]], PrimeQ[a1=2#+1]&&PrimeQ[a2=2a1+1]&&PrimeQ[a3=2a2+1]&&PrimeQ[a4=2a3+1]&&Prime\ Q[a5=2*a4+1] &] (from Vladimir Orlovsky (4vladimir(AT)gmail.com), May 01 2008)`
	CROSSREFS	`Cf. (A005384 and A005385), A007700, A023272, A023302, A057331, A005602.` `Sequence in context: A086695 A056568 A167398 this_sequence A059766 A033513 A128872` `Adjacent sequences: A023327 A023328 A023329 this_sequence A023331 A023332 A023333`
	KEYWORD	`nonn`
	AUTHOR	`David W. Wilson (davidwwilson(AT)comcast.net)`

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Last modified November 25 20:09 EST 2009. Contains 167514 sequences.

AT&T Labs Research