A056421 - OEIS

%I #6 Aug 22 2017 20:53:11

%S 4,6,16,45,72,404,456,2550,5144,26880,38568,367170,431776,3202964,

%T 8993712,33857520,63177816,636456776,803796696,6886253964,17456593904,

%U 79965511980,139069427016,1466861335900

%N Number of primitive (period n) step cyclic shifted sequences using a maximum of 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.

%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 Sum mu(d)*A056412(n/d) where d|n.

%K nonn

%O 1,1

%A _Marks R. Nester_