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 A056429 #9 Aug 22 2017 20:53:11 %S A056429 1,2,2,4,3,8,5,14,11,26,15,88,37,130,184,357,261,1346,805,3760,4434, %T A056429 9758,8385,47462,33781,108330,138767,408376,331185,2251816,1155735 %N A056429 Number of step cyclic shifted sequence structures using a maximum of two different symbols. %C A056429 See A056371 for an explanation of step shifts. Under step cyclic shifts, abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. Permuting the symbols will not change the structure. %D A056429 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 A056429 Use de Bruijn's generalization of Polya's enumeration theorem as discussed in reference. %F A056429 a(n) = A288627(n, 2) + 1. - _Andrew Howroyd_, Jun 13 2017 %Y A056429 Cf. A002729, A288627. %K A056429 nonn %O A056429 1,2 %A A056429 _Marks R. Nester_