%I #10 Aug 22 2017 20:53:10
%S 0,0,0,1,3,37,63,479,1316,8597,14619,155999,211231,1732907,5302823,
%T 21559909,43398413,466495335,625545865,5659500031,15126813765,
%U 72778025365,132561145173,1460519554091,2338565021382
%N Number of step shifted (decimated) sequence structures using exactly four 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 A056393(n)-A056392(n).
%Y Column 4 of A288620.
%Y Cf. A056378.
%K nonn
%O 1,5
%A _Marks R. Nester_