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 A001686 M0893 N0338 #21 Feb 01 2022 01:22:27 %S A001686 1,1,2,3,8,51,1538,599871,19417825808,1573273218577214751, %T A001686 124442887685693556895657990772138, %U A001686 311057821480221188367831306672353513246409033360367599771 %N A001686 From a continued fraction. %D A001686 N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). %D A001686 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). %H A001686 V. C. Harris, <a href="http://www.jstor.org/stable/2309559">Another proof of the infinitude of primes</a>, Amer. Math. Monthly, 63 (1956), 711. %F A001686 Denominator of continued fraction formed by terms of A001684. - _Sean A. Irvine_, Nov 13 2012 %Y A001686 Cf. A001684, A001685. %K A001686 nonn %O A001686 0,3 %A A001686 _N. J. A. Sloane_ %E A001686 a(11) from _Sean A. Irvine_, Nov 13 2012