A103797 Indices of n such that A019565(n)-1 is prime.

2, 3, 7, 9, 11, 21, 27, 29, 31, 39, 41, 47, 51, 53, 55, 61, 63, 67, 71, 81, 89, 91, 107, 113, 121, 123, 129, 131, 135, 139, 143, 149, 151, 157, 159, 163, 169, 175, 179, 183, 187, 191, 197, 199, 207, 211, 217, 223, 235, 241, 251, 259, 261, 269, 279, 281, 287, 295

Offset: 0

Author

Lei Zhou, Feb 22 2005

Keywords

• nonn

Examples

			A019565(0)=1, 1-1=0 is not prime;
A019565(1)=2, 2-1=1 is not prime;
A019565(2)=3, 3-1=2 is prime, so a(1)=2.
		

Crossrefs

Cf. A019565, A103796.

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}]