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 A056381 #6 Aug 22 2017 20:53:10 %S A056381 2,2,4,8,10,32,26,84,98,266,214,1200,702,2770,4328,8832,8230,44086, %T A056381 29202,135744,176720,419654,381490,2149068,1678244,5593294,7461064, %U A056381 22550600,19175158,134386396,71585134 %N A056381 Number of primitive (aperiodic) step shifted (decimated) sequences using a maximum of two different symbols. %C A056381 See A056371 for an explanation of step shifts. %D A056381 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 A056381 Sum mu(d)*A056371(n/d) where d divides n. %K A056381 nonn %O A056381 1,1 %A A056381 _Marks R. Nester_