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 A068596 #28 May 03 2019 07:21:25 %S A068596 1,0,1,1,11,44,169,588,1948,6560,23133,84565,317755,1198336,4509419, %T A068596 16909184,63409935,238609052,902444517,3429249843,13076666409, %U A068596 49977802752,191312873561,733365845820,2815437297416,10825960652800,41694907460224,160823207301705 %N A068596 Number of 4-ary Lyndon words whose trace and subtrace are both 0 mod 4. %C A068596 The trace of a word is the sum of its characters; the subtrace of a word is the sum of all products of pairs of its characters. %H A068596 Max Alekseyev, <a href="http://home.gwu.edu/~maxal/gpscripts/">PARI/GP scripts for miscellaneous math problems</a> %H A068596 F. Ruskey, <a href="http://combos.org/TSlyndonZ4">4-ary Lyndon words with given trace and subtrace</a> %Y A068596 Cf. A074403, A074404, A074405, A074406, A074407, A074408, A074409, A074410, A074411, A074412, A074413. %K A068596 nonn %O A068596 1,5 %A A068596 _Frank Ruskey_, Mar 28 2002 %E A068596 Terms a(15) onward from _Max Alekseyev_, Apr 09 2013