Number of n X 3 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 3 neighbors with the same value.

A164760

Number of n X 3 1..4 arrays with all 1s connected, all 2s connected, all 3s connected, all 4s connected, 1 in the upper left corner, 2 in the upper right corner, 3 in the lower left corner, 4 in the lower right corner, and with no element having more than 3 neighbors with the same value.

Terms

    a(0) =8a(1) =104a(2) =670a(3) =3096a(4) =11786a(5) =39564a(6) =121678a(7) =350992a(8) =964338a(9) =2550356a(10) =6541846a(11) =16366616a(12) =40107066a(13) =96586332a(14) =229176926a(15) =536895520a(16) =1243957122a(17) =2854431844a(18) =6494293670a(19) =14664265256a(20) =32889555658a(21) =73320539244a(22) =162562734830

External references