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 A056405 #6 Aug 22 2017 20:53:11 %S A056405 1,1,3,9,17,112,160,1182,3526,27550,60332,863283,1636608,19121869, %T A056405 84580104,501914374,1492170608,23751681540,47340359590,637742792823, %U A056405 2546703019081,18317620779149,49923584451714 %N A056405 Number of primitive (aperiodic) step shifted (decimated) sequence structures using a maximum of six different symbols. %C A056405 See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure. %D A056405 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 A056405 Sum mu(d)*A056395(n/d) where d|n. %Y A056405 Cf. A056385. %K A056405 nonn %O A056405 1,3 %A A056405 _Marks R. Nester_