A121979 Numbers k such that (2*k^2)^4 + 1 is prime.

1, 11, 12, 20, 24, 27, 28, 34, 40, 44, 61, 74, 79, 82, 95, 96, 119, 131, 136, 147, 148, 156, 164, 170, 173, 180, 187, 209, 211, 238, 252, 255, 269, 279, 299, 328, 337, 340, 343, 371, 379, 380, 388, 397, 413, 452, 462, 473, 476, 483, 516, 522, 527, 530, 539, 572

Offset: 1

Author

Alexander Adamchuk, Sep 10 2006

Keywords

• nonn
• easy
• changed

Comments

Corresponding primes of the form (2*k^2)^4 + 1 are {17, 3429742097, 6879707137, 409600000001, ...}.

There are consecutive twin pairs {a(n),a(n+1)} = {11,12}, {27,28}, {95,96},{147,148}, ...

Links

• G. C. Greubel, Table of n, a(n) for n = 1..5000

Crossrefs

Cf. A000068.

Programs

Mathematica

Select[Range[1000],PrimeQ[(2*#1^2)^4+1]&]

PARI

is(n)=isprime((2*n^2)^4+1) \\ Charles R Greathouse IV, Jun 13 2017