

A240099


Integers n such that 2n^k + 1, for k = 2..6, are prime.


1



1, 44250, 1004004, 3490575, 3517335, 5750115, 10729026, 19193559, 20251770, 25284039, 25552194, 30204801, 33733206, 39015405, 47518809, 52463445, 58370025, 69502971, 72009429, 77086380, 78510156, 83972646, 85955475, 89190969, 90499584, 92246199, 95374005
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OFFSET

1,2


COMMENTS

Note that 2n^7+1 may or may not be prime.
First n>1 such that 2n^k+1, for k=2..7, are prime, is a(4) = 3490575.
First n>1 such that 2n^k+1, for k=2..8, are prime, is 83972646.
Subsequence of A239925: a(2) = 44250 = A239925(4), a(3) = 1004004 = A239925(27).


LINKS

Table of n, a(n) for n=1..27.


MATHEMATICA

Select[Range[10^8], AllTrue[2#^Range[2, 6]+1, PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* Harvey P. Dale, Mar 18 2015 *)


CROSSREFS

Cf. A089001, A168550, A239874, A239925.
Sequence in context: A234426 A187436 A193055 * A245483 A015388 A257714
Adjacent sequences: A240096 A240097 A240098 * A240100 A240101 A240102


KEYWORD

nonn


AUTHOR

Zak Seidov, Apr 01 2014


STATUS

approved



