A115104 Numbers n such that 4*n^3 + 1 is prime.

1, 3, 4, 7, 9, 10, 19, 25, 34, 37, 39, 42, 49, 54, 55, 72, 73, 78, 85, 87, 93, 94, 102, 108, 109, 118, 138, 142, 147, 157, 160, 165, 168, 175, 192, 195, 202, 210, 214, 220, 228, 232, 243, 247, 249, 250, 252, 253, 258, 267, 273, 274, 279, 289, 297

Offset: 1

Author

Parthasarathy Nambi, Mar 02 2006

Keywords

• nonn

Comments

For any n in this sequence, 3*(4*n^3 + 1) has the same nonzero digits as its prime factors in base 2n. - Ely Golden, Dec 12 2016

Examples

			If n=94 then (4*n^3 + 1) = 3322337 (prime).
		

Links

• Ely Golden, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A001912. See A199307 for the actual primes.

See also A199364, A199365, A199366, A199367, A199368, A199369.

Programs

Mathematica

Select[Range[300], PrimeQ[4*#^3 + 1] &] (* Stefan Steinerberger, Mar 04 2006 *)

PARI

is(n)=isprime(4*n^3+1) \\ Charles R Greathouse IV, Feb 17 2017

Extensions

More terms from Stefan Steinerberger, Mar 04 2006