OFFSET
1,2
EXAMPLE
7 is there because the 7th prime is 17 and 2^17-1+10^7 is prime.
MATHEMATICA
Position[PrimeQ[Table[(2^Prime[n] - 1) + 10^n, {n, 10}]], True]
CROSSREFS
KEYWORD
nonn,more,changed
AUTHOR
Joao Carlos Leandro da Silva (zxawyh66(AT)yahoo.com), Feb 02 2006
EXTENSIONS
Edited by Don Reble, Jul 23 2006
a(10)-a(11) from Michael S. Branicky, Apr 15 2023
a(12)-a(13) from Michael S. Branicky, Nov 28 2024
STATUS
approved