OFFSET
1,2
COMMENTS
Searched up to 76856*2^100000 - 1 (9607*2^100003 - 1 is the format in the Yves Gallot's Proth Program)
FORMULA
a(n) = least integer greater than a(n-1) such that a(n-1)*2^a(n) - 1 is prime
PROG
(PARI) a=1; until(, print1(a, ", "); for(b=a+1, +oo, if(ispseudoprime(a*2^b-1), a=b; break()))) \\ Jeppe Stig Nielsen, Apr 29 2022
CROSSREFS
KEYWORD
hard,nonn
AUTHOR
Chad Davis (cad16(AT)po.cwru.edu)
EXTENSIONS
a(25)-a(27) from Kellen Shenton Apr 29 2022
STATUS
approved