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 A056423 #6 Aug 22 2017 20:53:11 %S A056423 6,15,50,210,456,4220,6960,57330,188810,1518558,3302916,45916780, %T A056423 83747280,933074430,3920355200,22075393725,62230996500,940379117630, %U A056423 1781757016320,22856963695482,87052415634120 %N A056423 Number of primitive (period n) step cyclic shifted sequences using a maximum of six different symbols. %C A056423 See A056371 for an explanation of step shifts. Under step cyclic shifts, abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. %D A056423 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 A056423 sum mu(d)*A056414(n/d) where d|n. %K A056423 nonn %O A056423 1,1 %A A056423 _Marks R. Nester_