A236547 Numbers k such that (2^(2k + 1) - 2)/3 + k - 1 is prime.

1, 2, 4, 10, 14, 28, 54, 62, 124, 592, 1088, 3154, 3920, 5564, 26510, 28674, 65124

Offset: 1

Author

Robin Garcia, Jan 28 2014

Keywords

• nonn

Comments

These primes are represented in the numeral system described in A235860 with the digit "2" followed to the right with k-1 "12" strings.

Examples

			For n = 2, (2^5 - 2)/3 + 1 = 11, which is prime, so 2 is in the sequence.
		

Crossrefs

Cf. A235860.

Programs

PARI

isok(n) = isprime((2^(2*n+1) -2)/3 + n-1); \\ Michel Marcus, Jan 28 2014

Extensions

a(1) inserted and a(15)-a(17) from Michael S. Branicky, Jul 29 2024