Array read by antidiagonals, generated by the matrix M = [1,1,1;1,N,1;1,1,1].

Terms

a(0) =1a(1) =1a(2) =2a(3) =1a(4) =3a(5) =6a(6) =1a(7) =4a(8) =9a(9) =16a(10) =1a(11) =5a(12) =14a(13) =27a(14) =44a(15) =1a(16) =6a(17) =21a(18) =48a(19) =81a(20) =120a(21) =1a(22) =7a(23) =30a(24) =85a(25) =164a(26) =243a(27) =328a(28) =1a(29) =8