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 A098857 #16 Oct 04 2024 11:23:54 %S A098857 1,2,18,40,50,60,62,2688,2880,23678,35076 %N A098857 Numbers k such that 4^k*(2^k - 1) - 1 is prime. %o A098857 (PARI) is(n)=ispseudoprime(4^n*(2^n-1)-1) \\ _Charles R Greathouse IV_, Jun 13 2017 %o A098857 (Magma) [k: k in [1..100] | IsPrime(4^k*(2^k-1)-1)]; // _Jinyuan Wang_, Mar 19 2020 %Y A098857 Cf. A098856 ((4^k)*(2^k - 1) + 1 is prime). %K A098857 nonn,more %O A098857 1,2 %A A098857 _Pierre CAMI_, Oct 11 2004 %E A098857 a(10) from _Ray G. Opao_, Sep 19 2005 %E A098857 a(11) from _Michael S. Branicky_, Oct 04 2024