A103796 Indices of n such that A019565(n)+1 is prime.

0, 1, 3, 5, 7, 11, 13, 15, 17, 19, 23, 27, 31, 35, 37, 43, 45, 47, 51, 57, 59, 67, 73, 79, 83, 85, 97, 99, 107, 111, 119, 123, 133, 135, 145, 151, 153, 155, 159, 163, 167, 173, 175, 185, 193, 201, 203, 211, 213, 215, 233, 245, 251, 253, 257, 259, 263, 267, 271, 277

Offset: 0

Author

Lei Zhou, Feb 22 2005

Keywords

• nonn

Examples

			A019565(0)=1, 1+1=2 is prime, so a(1)=0;
A019565(1)=2, 2+1=3 is prime, so a(2)=1;
A019565(2)=3, 3+1=4 is not prime
A019565(3)=6, 6+1=7 is prime, so a(3)=3;
		

Crossrefs

Cf. A019565.

Programs

Mathematica

A019565 = Function[tn, k1 = tn; o = 1; tt = 1; While[k1 > 0, k2 = Mod[k1, 2]; If[k2 == 1, tt = tt*Prime[o]]; k1 = (k1 - k2)/2; o = o + 1]; tt]; Do[cp = A019565[n] + 1; If[PrimeQ[cp], Print[n]], {n, 0, 1000} ]