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 A230810 #10 Dec 11 2016 02:51:44 %S A230810 3,3465253618399,374166120095639,12959269432331237,44202753561285409, %T A230810 1640293473202755797,1640293473202755799,10623546148468360249 %N A230810 Smallest of 3 consecutive odd numbers that are primes or strong pseudoprime to base 2. %C A230810 Since a(7) = a(6) + 2, the number a(6) = 1640293473202755797 actually starts a sequence of four consecutive odd numbers which are prime or strong pseudoprimes to base 2. - _M. F. Hasler_, Dec 08 2016 %H A230810 S. S. Gupta, <a href="http://www.shyamsundergupta.com/canyoufind.htm">Can You Find no. 48</a>, Oct. 2016. %e A230810 3465253618399 is in sequence because 3465253618399, 3465253618401, 3465253618403 is a set of 3 consecutive odd number where 3465253618401 is strong pseudoprime base 2 and others are prime. %Y A230810 Cf. A001262, A001567, A230667, A230808. %K A230810 nonn,hard,more %O A230810 1,1 %A A230810 _Shyam Sunder Gupta_, Oct 30 2013 %E A230810 Edited by _M. F. Hasler_, Dec 08 2016