Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no two horizontal or vertical neighbors of any element equal.

A194888

Number of lower triangles of an n X n 0..3 array with new values introduced in row major order 0..3 and no two horizontal or vertical neighbors of any element equal.

Terms

    a(0) =1a(1) =3a(2) =24a(3) =192a(4) =1152a(5) =5760a(6) =26880a(7) =118272a(8) =506880a(9) =2119680a(10) =8761344a(11) =35807232a(12) =145539072a(13) =588349440a(14) =2372075520a(15) =9538240512a(16) =38303170560a(17) =153613762560a(18) =615659864064

External references