A240099 Integers n such that 2n^k + 1, for k = 2..6, are prime.

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

Offset: 1

Author

Zak Seidov, Apr 01 2014

Keywords

• nonn

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).

Crossrefs

Cf. A089001, A168550, A239874, A239925.

Programs

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 *)