%I #10 Apr 07 2021 19:45:51
%S 1,6,48,528,8160,179520,5666304,257819136,16962407424,1617060046848,
%T 223709857824768,44962767953608704,13140310268741124096,
%U 5587767779596757434368,3459297434976642415460352
%N 1/4 of the number of 4-colorings of a planar n X n X n triangular grid.
%Y 4th row of A182797/4, A182798/4.
%K nonn
%O 1,2
%A _R. H. Hardin_, Dec 27 2008
%E a(14) from _Alois P. Heinz_, Dec 03 2010
%E a(15) from _Alois P. Heinz_, Mar 11 2016