1,2

Table of n, a(n) for n=1..9.

7 is there because the 7th prime is 17 and 2^17-1+10^7 is prime.

Position[PrimeQ[Table[(2^Prime[n] - 1) + 10^n, {n, 10}]], True]

Sequence in context: A103173 A098863 A053960 * A168222 A323384 A140221

Adjacent sequences: A114053 A114054 A114055 * A114057 A114058 A114059

nonn

Joao Carlos Leandro da Silva (zxawyh66(AT)yahoo.com), Feb 02 2006

Edited by Don Reble, Jul 23 2006

approved