%I A056453
%S A056453 0,0,2,2,6,6,14,14,30,30,62,62,126,126,254,254,510,510,1022,1022,2046,
%T A056453 2046,4094,4094,8190,8190,16382,16382,32766,32766,65534
%N A056453 Palindromes using exactly two different symbols.
%D A056453 M. R. Nester (1999). Mathematical investigations of some plant interaction 
               designs. PhD Thesis. University of Queensland, Brisbane, Australia.
%F A056453 2^[(n+1)/2]-2.
%Y A056453 Cf. A016116, A000918.
%Y A056453 Sequence in context: A060549 A120690 A165124 this_sequence A034422 A140833 
               A071908
%Y A056453 Adjacent sequences: A056450 A056451 A056452 this_sequence A056454 A056455 
               A056456
%K A056453 nonn
%O A056453 1,3
%A A056453 Marks R. Nester (nesterm(AT)dpi.qld.gov.au)