A331205 a(n) = least prime of the form 2^m - 2^n + 1.

2, 3, 5, 549755813881, 17, 97, 193, 140737488355201, 257, 7681, 15361, 134215681, 12289, 8380417, 114689

Offset

0,1

Comments

a(15) = 2^447 - 2^15 + 1 is too large to be represented in the data.

Links

Hugo Pfoertner, Table of n, a(n) for n = 0..62

Example

See A331204.

Prog

(PARI) for(n=0, 14, for(m=n+1, oo, k=2^m-2^n+1; if(isprime(k), print1(k, ", "); break)))

Crossrefs

Cf. A181692, A331204 (corresponding values of m).

Sequence in context: A305192 A141186 A078682 * A075174 A075176 A134972

Adjacent sequences: A331202 A331203 A331204 * A331206 A331207 A331208

Keyword

nonn

Author

Hugo Pfoertner, Jan 12 2020

Status

approved