A361563 Wagstaff numbers that are of the form 4*k + 1.

5, 13, 17, 61, 101, 313, 701, 1709, 2617, 10501, 42737, 95369, 138937, 267017, 374321

Offset

1,1

Comments

15135397 is also in the sequence, but may not be the next term.

Links

Table of n, a(n) for n=1..15.

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

Formula

Intersection of A000978 and A002144.

Prog

(Python)
from itertools import count, islice
from sympy import prime, isprime
def A361563_gen(): # generator of terms
    return filter(lambda p: not p&2 and isprime(((1<<p)+1)//3), (prime(n) for n in count(2)))
A361563_list = list(islice(A361563_gen(), 7)) # Chai Wah Wu, Mar 21 2023

Crossrefs

Cf. A000978 (Wagstaff numbers), A002144 (primes of form 4*k + 1), A112634, A361562.

Sequence in context: A276260 A350379 A145040 * A195549 A294132 A125146

Adjacent sequences: A361560 A361561 A361562 * A361564 A361565 A361566

Keyword

nonn,more

Author

Jorge Coveiro, Mar 15 2023

Status

approved