A181494 Twin primes (A001097) of the form 3*2^k +- 1.

5, 7, 11, 13, 191, 193, 786431, 786433

Offset: 1

Author

M. F. Hasler, Oct 30 2010

Keywords

• more
• nonn

Crossrefs

Cf. A001097, A001359, A006512, A014574.

Programs

PARI

for( k=1,999, ispseudoprime(3<
				

Formula

A181494 = A181491 union A181492.

A181494(n) = A181493(ceiling(n/2)) + (-1)^n = A007283(A181490(ceiling(n/2))) + (-1)^n.