A194889 - OEIS

A194889

Number of lower triangles of an n X n 0..4 array with new values introduced in row major order 0..4 and no two horizontal or vertical neighbors of any element equal

%I #5 Dec 18 2015 18:17:44

%S 1,3,33,1620,136080,17962560,3751608960,1233597237120,641473938397440,

%T 526921921428975360

%N Number of lower triangles of an n X n 0..4 array with new values introduced in row major order 0..4 and no two horizontal or vertical neighbors of any element equal

%C Column 4 of A194893

%e Some solutions for 4X4

%e ..0........0........0........0........0........0........0........0

%e ..1.2......0.1......1.2......1.1......0.1......1.2......0.1......1.1

%e ..3.0.1....2.3.4....1.3.0....2.3.4....2.1.3....1.2.3....2.1.0....2.3.3

%e ..4.0.3.2..2.0.1.1..0.4.2.1..2.0.1.1..2.0.4.4..4.0.1.4..2.3.0.1..2.0.4.2

%K nonn

%O 1,2

%A _R. H. Hardin_ Sep 04 2011