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 A208276 #21 May 15 2019 19:16:22 %S A208276 0,0,0,0,0,0,0,0,1,3,8,13,19,32,45,64,89,124,175,251,361,502,693,944, %T A208276 1264,1713,2361,3169,4232,5749,7750,10403,14011,18667,24958,33389, %U A208276 44540,59565,79343,105659,141147,188231,250568,333737,445316,593366,792172,1059097,1416055,1893726,2532703,3390284,4540673,6086093,8167163,10964612,14731767,19806649,26651383,35893886,48374139,65247459,88069251,118968378 %N A208276 Number of Poulet numbers (or pseudoprimes to base 2, A001567) less than 2^n. %H A208276 Jan Feitsma, <a href="http://www.janfeitsma.nl/math/psp2/statistics">The pseudoprimes below 2^64 - statistics</a> %H A208276 Jan Feitsma and William Galway, <a href="http://www.cecm.sfu.ca/Pseudoprimes/index-2-to-64.html">Tables of pseudoprimes and related data</a> %o A208276 (PARI) count=0;for(e=1,32,forcomposite(n=2^(e-1),2^e-1,if(n%2 && Mod(2,n)^(n-1)==1,count++)); print1(count", ")); \\ _Hans Loeblich_, May 15 2019 %Y A208276 Cf. A001567, A055550, A108797, A225005 %K A208276 nonn %O A208276 1,10 %A A208276 _Washington Bomfim_, Feb 25 2012 %E A208276 a(50)-a(64) from Feitsma's website, added by _Max Alekseyev_, Apr 23 2013