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%I M4204 #10 Jul 08 2015 04:01:57
%S 1,6,30,150,750,3726,18438,90966,447918,2201622,10809006,52999446,
%T 259668942,1271054982,6218232414,30399142614
%N Trails of length n on cubic lattice.
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A. J. Guttmann, <a href="http://dx.doi.org/10.1088/0305-4470/18/4/009">Lattice trails II: numerical results</a>, J. Phys. A 22 (1989), 575-588.
%K nonn,walk
%O 0,2
%A _N. J. A. Sloane_.