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 A056396 #10 Aug 22 2017 20:53:10 %S A056396 0,1,2,5,5,19,13,47,51,139,107,623,351,1399,2171,4463,4115,22111, %T A056396 14601,68015,88375,209935,190745,1075199,839127,2796999,3730583, %U A056396 11276703,9587579,67195519,35792567 %N A056396 Number of step shifted (decimated) sequence structures using exactly two different symbols. %C A056396 See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure. %D A056396 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 A056396 A056391(n)-1. %Y A056396 Column 2 of A288620. %Y A056396 Cf. A056376. %K A056396 nonn %O A056396 1,3 %A A056396 _Marks R. Nester_