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

Author

Jorge Coveiro, Mar 15 2023

Keywords

• nonn
• more

Comments

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

Links

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

Crossrefs

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

Programs

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<A361563_list = list(islice(A361563_gen(),7)) # Chai Wah Wu, Mar 21 2023

Formula

Intersection of A000978 and A002144.