Number of n X 3 0..1 arrays with rows and columns unimodal and antidiagonals nondecreasing.

Terms

a(0) =7a(1) =28a(2) =78a(3) =180a(4) =371a(5) =707a(6) =1269a(7) =2170a(8) =3563a(9) =5650a(10) =8692a(11) =13020a(12) =19047a(13) =27281a(14) =38339a(15) =52962a(16) =72031a(17) =96584a(18) =127834a(19) =167188a(20) =216267a(21) =276927a(22) =351281a(23) =441722a(24) =550947a(25) =681982a(26) =838208a(27) =1023388a(28) =1241695a(29) =1497741