This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A361563 #55 Apr 15 2023 16:55:48 %S A361563 5,13,17,61,101,313,701,1709,2617,10501,42737,95369,138937,267017, %T A361563 374321 %N A361563 Wagstaff numbers that are of the form 4*k + 1. %C A361563 15135397 is also in the sequence, but may not be the next term. %H A361563 Jorge Coveiro, <a href="https://www.mersenneforum.org/showthread.php?t=28546">Possible 'Formula' for Wagstaff numbers</a>, mersenneforum.org. %F A361563 Intersection of A000978 and A002144. %o A361563 (Python) %o A361563 from itertools import count, islice %o A361563 from sympy import prime, isprime %o A361563 def A361563_gen(): # generator of terms %o A361563 return filter(lambda p: not p&2 and isprime(((1<<p)+1)//3), (prime(n) for n in count(2))) %o A361563 A361563_list = list(islice(A361563_gen(),7)) # _Chai Wah Wu_, Mar 21 2023 %Y A361563 Cf. A000978 (Wagstaff numbers), A002144 (primes of form 4*k + 1), A112634, A361562. %K A361563 nonn,more %O A361563 1,1 %A A361563 _Jorge Coveiro_, Mar 15 2023