A058221 Next-to-smallest k such that 2^(2^n) - k is prime.

2, 5, 15, 17, 17, 83, 173, 357, 629, 179, 2543, 8067, 5619, 29027, 38783, 99267

Offset: 1

Author

Warren D. Smith, Nov 30 2000

Keywords

• nonn
• hard
• more

Crossrefs

Cf. A058220.

Programs

PARI

a(n) = my(N = 2^(2^n)); N - precprime(precprime(N)-1) \\ Michel Marcus, Jun 29 2013

Extensions

a(15) from Jinyuan Wang, Jun 06 2020

a(16) from Michael S. Branicky, Apr 23 2023