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

1,1

Links

Table of n, a(n) for n=1..16.

Prog

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

Crossrefs

Cf. A058220.

Sequence in context: A146109 A146108 A032841 * A349734 A146122 A263457

Adjacent sequences: A058218 A058219 A058220 * A058222 A058223 A058224

Keyword

nonn,hard,more

Author

Warren D. Smith, Nov 30 2000

Extensions

a(15) from Jinyuan Wang, Jun 06 2020

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

Status

approved