1,2

Searched up to 76856*2^100000 - 1 (9607*2^100003 - 1 is the format in the Yves Gallot's Proth Program)

Y. Gallot, Proth.exe: Windows Program for Finding Large Primes

a(n) = least integer greater than a(n-1) such that a(n-1)*2^a(n) - 1 is prime

Sequence in context: A073628 A067938 A018457 this_sequence A112777 A047612 A123886

Adjacent sequences: A046806 A046807 A046808 this_sequence A046810 A046811 A046812

hard,nonn

Chad Davis (cad16(AT)po.cwru.edu)