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 A056388 #6 Aug 22 2017 20:53:10 %S A056388 0,0,0,12,60,792,1404,10704,31200,204972,349956,3727128,5065804, %T A056388 41572908,127198968,517279416,1041517620,11195605728,15012935676, %U A056388 135825494568,363040468328,1746669815460,3181465294092 %N A056388 Number of primitive (aperiodic) step shifted (decimated) sequences using exactly four different symbols. %C A056388 See A056371 for an explanation of step shifts. %D A056388 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 A056388 sum mu(d)*A056378(n/d) where d|n. %K A056388 nonn %O A056388 1,4 %A A056388 _Marks R. Nester_