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 A056377 #7 Aug 22 2017 20:53:10 %S A056377 0,0,3,21,39,288,309,1659,3102,14148,17157,136227,130995,790128, %T A056377 1791489,5427597,8047839,64467180,64486017,437324331,871627041, %U A056377 3136899816,4278115101,35355632943,42359479638 %N A056377 Number of step shifted (decimated) sequences using exactly three different symbols. %C A056377 See A056371 for an explanation of step shifts. %D A056377 M. R. Nester (1999). Mathematical investigations of some plant interaction designs. PhD Thesis. University of Queensland, Brisbane, Australia. [See A056391 for pdf file of Chap. 2] %F A056377 A056372(n)-3*A056371(n)+3. %Y A056377 Cf. A056372. %K A056377 nonn %O A056377 1,3 %A A056377 _Marks R. Nester_