A232238 Primes p such that p+2 and q are primes, where q is concatenation of binary representations of p and p+2: q = p * 2^L + p+2, where L is the length of binary representation of p+2: L=A070939(p+2).

3, 5, 17, 71, 269, 1049, 1151, 1721, 5099, 5279, 5657, 6299, 6569, 6779, 7307, 7589, 16451, 16649, 16691, 19079, 19139, 19211, 19841, 19961, 20771, 20981, 21011, 21059, 21599, 22619, 22961, 23201, 23369, 23741, 23909, 24419, 26729, 26951, 27689, 28109, 28409, 28751, 29129

Offset: 1

Author

Alex Ratushnyak, Nov 20 2013

Keywords

• nonn
• base
• less

Examples

			3 is 11 in binary, 5 is 101. Because 11101 = 29d is a prime, 3 is in the sequence.
5 is 101 in binary, 7 is 111, and because 101111 = 47d is a prime, 5 is in the sequence.
		

Crossrefs

Cf. A000040, A070939, A232236.

Formula

A232236(n) = a(n) * 2^A070939(a(n)+2) + a(n)+2.