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 A056398 #10 Aug 22 2017 20:53:10 %S A056398 0,0,0,1,3,37,63,479,1316,8597,14619,155999,211231,1732907,5302823, %T A056398 21559909,43398413,466495335,625545865,5659500031,15126813765, %U A056398 72778025365,132561145173,1460519554091,2338565021382 %N A056398 Number of step shifted (decimated) sequence structures using exactly four different symbols. %C A056398 See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure. %D A056398 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 A056398 A056393(n)-A056392(n). %Y A056398 Column 4 of A288620. %Y A056398 Cf. A056378. %K A056398 nonn %O A056398 1,5 %A A056398 _Marks R. Nester_