%I A005396 M4043
%S A005396 0,6,0,30,24,168,288,1170,2760
%N A005396 Number of 2n-step polygons on honeycomb.
%D A005396 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, 
               Academic Press, 1995 (includes this sequence).
%D A005396 M. E. Fisher and M. F. Sykes, Excluded-volume problem and the Ising model 
               of ferromagnetism, Phys. Rev. 114 (1959), 45-58.
%Y A005396 Sequence in context: A062254 A028849 A138704 this_sequence A056462 A047762 
               A167316
%Y A005396 Adjacent sequences: A005393 A005394 A005395 this_sequence A005397 A005398 
               A005399
%K A005396 nonn
%O A005396 2,2
%A A005396 N. J. A. Sloane (njas(AT)research.att.com).