A046809 a(n) is the least integer greater than a(n-1) such that a(n-1)*2^a(n) - 1 is prime, a(1) = 1.
1, 2, 4, 5, 8, 10, 11, 26, 286, 365, 602, 630, 713, 808, 1327, 3561, 3566, 5286, 5477, 10600, 13485, 15441, 17339, 76856, 277718, 279098, 977278, 3437687, 3564664, 3883403, 4254462, 4972164
Offset: 1
Links
- Chris K. Caldwell, The Prime Pages, 488639*2^3437688-1 (977278*2^3437687-1)
- Chris K. Caldwell, The Prime Pages, 3437687*2^3564664-1
- Chris K. Caldwell, The Prime Pages, 445583*2^3883406-1 (3564664*2^3883403-1)
- Chris K. Caldwell, The Prime Pages, 3883403*2^4254462-1
- Chris K. Caldwell, The Prime Pages, 2127231*2^4972165-1 (4254462*2^4972164-1)
- Y. Gallot, Proth.exe: Windows Program for Finding Large Primes
Crossrefs
Cf. A046808.
Programs
-
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
Extensions
a(25)-a(27) from Kellen Shenton Apr 29 2022
a(28)-a(32) from Kellen Shenton, Jun 15 2025
Comments