%I #10 Aug 22 2017 20:53:10
%S 0,0,1,4,8,50,54,284,525,2370,2872,22748,21866,131750,298792,904918,
%T 1341518,10745090,10748218,72889084,145274556,522819590,713023210,
%U 5892634240,7059926605,35300985550,70604008204
%N Number of step shifted (decimated) sequence structures using exactly three different symbols.
%C See A056371 for an explanation of step shifts. Permuting the symbols will not change the structure.
%D 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 A056392(n)-A056391(n).
%Y Column 3 of A288620.
%Y Cf. A056377.
%K nonn
%O 1,4
%A _Marks R. Nester_