A077498 Primes of the form 2^r*7^s + 1.

2, 3, 5, 17, 29, 113, 197, 257, 449, 1373, 3137, 50177, 65537, 114689, 268913, 470597, 614657, 1075649, 3294173, 7340033, 9834497, 210827009, 275365889, 359661569, 469762049, 1129900997, 1438646273, 1927561217, 7909306973, 52613349377, 126548911553, 215886856193, 863547424769, 2024782584833

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..1463 (terms < 10^500)

Example

197 = 2^2*7^2 + 1 is a member.

Maple

N:= 10^13: # for terms <= N+1
sort(select(isprime, [seq(seq(2^r*7^s+1, s=0..ilog[7](N/2^r)), r=0..ilog2(N))])); # Robert Israel, May 20 2026

Crossrefs

Cf. A005109, A077497, A077499, A077500.

Sequence in context: A348062 A349678 A029972 * A118958 A259596 A189536

Adjacent sequences: A077495 A077496 A077497 * A077499 A077500 A077501

Keyword

nonn

Author

Amarnath Murthy, Nov 07 2002

Extensions

Corrected and extended by Ray Chandler, Aug 02 2003

More terms from Robert Israel, May 20 2026

Status

approved