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 A020235 #21 Feb 16 2025 08:32:33 %S A020235 91,121,671,703,1541,1729,1891,2821,3281,3367,3751,5551,7381,8401, %T A020235 8911,10585,11011,12403,14383,15203,16471,16531,18721,19345,23521, %U A020235 24661,24727,28009,29341,30857,31621,32791,38503,44287,46999,47197,49051,49141,53131 %N A020235 Strong pseudoprimes to base 9. %H A020235 Amiram Eldar, <a href="/A020235/b020235.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..369 from R. J. Mathar) %H A020235 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/StrongPseudoprime.html">Strong Pseudoprime</a> %H A020235 <a href="/index/Ps#pseudoprimes">Index entries for sequences related to pseudoprimes</a> %Y A020235 Cf. A020138, A020229 (base 3), A020307 (base 81). %K A020235 nonn %O A020235 1,1 %A A020235 _David W. Wilson_