%I A056338
%S A056338 0,0,0,1,6,37,183,876,3930,17179,73095,306323,1267266,5198374,21182337,
%T A056338 85910040,347187210,1399447578,5629911015,22616239535,90754854843,
%U A056338 363890053582,1458172596903,5840531328120,23385650196084
%N A056338 Number of primitive (aperiodic) reversible string structures with n beads 
               using exactly four different colors.
%C A056338 A string and its reverse are considered to be equivalent. Permuting the 
               colors will not change the structure.
%D A056338 M. R. Nester (1999). Mathematical investigations of some plant interaction 
               designs. PhD Thesis. University of Queensland, Brisbane, Australia.
%F A056338 A056333(n)-A056332(n).
%Y A056338 Cf. A056320.
%Y A056338 Sequence in context: A097297 A047670 A129552 this_sequence A056328 A156185 
               A057418
%Y A056338 Adjacent sequences: A056335 A056336 A056337 this_sequence A056339 A056340 
               A056341
%K A056338 nonn
%O A056338 1,5
%A A056338 Marks R. Nester (nesterm(AT)dpi.qld.gov.au)