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 A058781 #14 Nov 07 2023 03:22:27
%S A058781 3,7,25,41,45,63,83,131,147,175,425,449,469,651,1345,1839,1883,1913,
%T A058781 2177,2551,2907,3675,6071,11743,14641,38685,40857,47761,97243
%N A058781 Numbers k such that k^2 * 2^k - 1 is prime.
%C A058781 If it exists, a(30) > 200000. - _Hugo Pfoertner_, Nov 07 2023
%H A058781 Steven Harvey, <a href="http://harvey563.tripod.com/GeneralizedHyperWoodall.txt">Generalized HyperWoodall Primes</a>
%t A058781 Do[ If[ PrimeQ[ n^2*2^n - 1 ], Print[n] ], {n, 1, 5000} ]
%o A058781 (PARI) is(n)=ispseudoprime(n^2*2^n-1) \\ _Charles R Greathouse IV_, May 22 2017
%Y A058781 Cf. A058780.
%K A058781 nonn
%O A058781 1,1
%A A058781 _Robert G. Wilson v_, Jan 02 2001
%E A058781 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Jan 05 2008