Array read by ascending antidiagonals: A(n, k) = k*(10^n - 1)/9 with k >= 0.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =1a(5) =0a(6) =0a(7) =11a(8) =2a(9) =0a(10) =0a(11) =111a(12) =22a(13) =3a(14) =0a(15) =0a(16) =1111a(17) =222a(18) =33a(19) =4a(20) =0a(21) =0a(22) =11111a(23) =2222a(24) =333a(25) =44a(26) =5a(27) =0a(28) =0a(29) =111111