Number of n X 4 0..2 arrays with rows unimodal and columns nondecreasing.

Terms

a(0) =46a(1) =548a(2) =3526a(3) =15779a(4) =55438a(5) =163746a(6) =424326a(7) =992607a(8) =2138488a(9) =4305730a(10) =8191976a(11) =14853709a(12) =25840868a(13) =43366252a(14) =70515252a(15) =111501861a(16) =171977322a(17) =259398184a(18) =383460946a(19) =556610879a(20) =794633026a(21) =1117333790a(22) =1549321930a(23) =2120898195