Array A read by upward antidiagonals: A(n,k) = ((2*n+1)*9^k-1)/2, n,k >= 0.

Terms

a(0) =0a(1) =1a(2) =4a(3) =2a(4) =13a(5) =40a(6) =3a(7) =22a(8) =121a(9) =364a(10) =4a(11) =31a(12) =202a(13) =1093a(14) =3280a(15) =5a(16) =40a(17) =283a(18) =1822a(19) =9841a(20) =29524a(21) =6a(22) =49a(23) =364a(24) =2551a(25) =16402a(26) =88573a(27) =265720a(28) =7a(29) =58