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Number of step cyclic shifted sequence structures using exactly four different symbols.
1

%I #9 Aug 22 2017 20:53:11

%S 0,0,0,1,1,11,13,83,162,930,1369,13730,16421,124702,355793,1356781,

%T 2555043,25933814,32931815,283330733,720489755,3308255032,5763641923,

%U 60874698532,93543112676,600086810852

%N Number of step cyclic shifted sequence structures using exactly four different symbols.

%C See A056371 for an explanation of step shifts. Under step cyclic shifts, abcde, bdace, bcdea, cdeab and daceb etc. are equivalent. 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 A056431(n)-A056430(n).

%Y Column 4 of A288627.

%Y Cf. A056417.

%K nonn

%O 1,6

%A _Marks R. Nester_