A361562 Wagstaff numbers that are of the form 4*k + 3.

3, 7, 11, 19, 23, 31, 43, 79, 127, 167, 191, 199, 347, 3539, 5807, 10691, 11279, 12391, 14479, 83339, 117239, 127031, 141079, 269987, 986191, 4031399

Offset

1,1

Comments

13347311 and 13372531 are also in the sequence, but may not be the next terms.

Links

Table of n, a(n) for n=1..26.

Jorge Coveiro, Possible 'Formula' for Wagstaff numbers, mersenneforum.org.

Formula

Intersection of A000978 and A002145.

Prog

(Python)
from itertools import count, islice
from sympy import prime, isprime
def A361562_gen(): # generator of terms
    return filter(lambda p: p&2 and isprime(((1<<p)+1)//3), (prime(n) for n in count(2)))
A361562_list = list(islice(A361562_gen(), 10)) # Chai Wah Wu, Mar 21 2023

Crossrefs

Cf. A000978 (Wagstaff numbers), A002145 (primes of form 4*k+3), A112633, A361563.

Sequence in context: A002052 A369249 A092109 * A277878 A117991 A118260

Adjacent sequences: A361559 A361560 A361561 * A361563 A361564 A361565

Keyword

nonn,more

Author

Jorge Coveiro, Mar 15 2023

Status

approved