Number of 3 X 3 0..n arrays with rows in lexicographically nondecreasing order and columns in nonincreasing order.

A229775

Number of 3 X 3 0..n arrays with rows in lexicographically nondecreasing order and columns in nonincreasing order.

Terms

    a(0) =20a(1) =322a(2) =3232a(3) =21331a(4) =103222a(5) =397460a(6) =1287672a(7) =3647349a(8) =9281272a(9) =21642038a(10) =46934680a(11) =95749927a(12) =185397226a(13) =343142248a(14) =610590224a(15) =1049496105a(16) =1749325212a(17) =2836933738a(18) =4488787184a(19) =6946186555a(20) =10534026910a(21) =15683670652a(22) =22960578760

External references