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 A056402 #6 Aug 22 2017 20:53:11 %S A056402 1,1,3,8,13,65,67,322,573,2495,2979,23294,22217,133081,300947,909050, %T A056402 1345633,10766559,10762819,72954582,145362861,523026545,713213955, %U A056402 5893685746,7060765719,35303760331 %N A056402 Number of primitive (aperiodic) step shifted (decimated) sequence structures using a maximum of three different symbols. %C A056402 See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure. %D A056402 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 A056402 Sum mu(d)*A056392(n/d) where d|n. %Y A056402 Cf. A056382. %K A056402 nonn %O A056402 1,3 %A A056402 _Marks R. Nester_