A192992 Odd n > 1 such that n+1 is a semiprime times a power of two.

7, 11, 15, 17, 19, 23, 27, 29, 31, 35, 39, 41, 43, 47, 49, 51, 55, 59, 63, 65, 67, 69, 71, 75, 77, 79, 83, 87, 91, 95, 97, 99, 101, 103, 109, 111, 113, 115, 119, 123, 127, 129, 131, 135, 137, 139, 143, 147, 151, 153, 155, 159, 163, 167, 169, 171, 173, 175

Offset: 1

Author

Jonathan Vos Post, Jul 13 2011

Keywords

• nonn
• easy

Comments

Odd n such that n+1 is in A192991.

This is to thin numbers A192868 as semiprimes A001358 are to primes A000040.

Examples

			239 is in the sequence because 239+1 = 240 = 6th semiprime * 2^4 = 3 * 5 * 16.
		

Crossrefs

Cf. A005408, A001358, A192868, A192991.

Formula

a(n) = A192991(n) - 1.