%I #10 Aug 22 2017 20:53:13
%S 0,0,0,0,0,0,1,1,10,10,65,65,350,349,1701,1700,7770,7760,34105,34095,
%T 145749,145685,611501,611435,2532530,2532180,10391735,10391395,
%U 42355950,42354239,171798901
%N Number of primitive (aperiodic) palindromic structures using exactly four different symbols.
%C 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 A056478(n)-A056477(n).
%Y Column 4 of A284826.
%Y Cf. A056465.
%K nonn
%O 1,9
%A _Marks R. Nester_