1/20 of the number of (n+1) X 3 0..4 arrays with every 2 X 2 subblock strictly increasing clockwise or counterclockwise with one decrease.

A183712

1/20 of the number of (n+1) X 3 0..4 arrays with every 2 X 2 subblock strictly increasing clockwise or counterclockwise with one decrease.

Terms

    a(0) =5a(1) =17a(2) =54a(3) =174a(4) =559a(5) =1797a(6) =5776a(7) =18566a(8) =59677a(9) =191821a(10) =616574a(11) =1981866a(12) =6370351a(13) =20476345a(14) =65817520a(15) =211558554a(16) =680016837a(17) =2185791545a(18) =7025832918a(19) =22583273462a(20) =72589861759a(21) =233327025821a(22) =749987665760

External references