%I A056450
%S A056450 4,4,16,16,64,64,256,256,1024,1024,4096,4096,16384,16384,65536,65536,
%T A056450 262144,262144,1048576,1048576,4194304,4194304,16777216,16777216,
%U A056450 67108864,67108864,268435456,268435456
%N A056450 Palindromes using a maximum of four different symbols.
%D A056450 M. R. Nester (1999). Mathematical investigations of some plant interaction 
               designs. PhD Thesis. University of Queensland, Brisbane, Australia.
%F A056450 4^[(n+1)/2].
%Y A056450 Cf. A016116.
%Y A056450 Sequence in context: A160020 A075882 A125757 this_sequence A141125 A164111 
               A164906
%Y A056450 Adjacent sequences: A056447 A056448 A056449 this_sequence A056451 A056452 
               A056453
%K A056450 nonn
%O A056450 1,1
%A A056450 Marks R. Nester (nesterm(AT)dpi.qld.gov.au)