Number of nX3 0..2 arrays with rows and columns unimodal.

Terms

a(0) =22a(1) =484a(2) =6166a(3) =51136a(4) =310396a(5) =1492552a(6) =5995781a(7) =20879061a(8) =64727664a(9) =182215264a(10) =472897132a(11) =1144905802a(12) =2610251996a(13) =5646952970a(14) =11664925145a(15) =23128319257a(16) =44207709722a(17) =81762385076a(18) =146787187114a(19) =256501341004a(20) =437310109972