%I #13 Nov 01 2019 10:17:36

%S 1,2,3,6,19,138,5555,5661606,8017014805939,549978189515061145367082,

%T 75619002235584922846322716556474301506401613843,

%U 615505010930370584284868847397460604890896977173300806488671348925702765535678512305286

%N a(n) = the sum of the terms in the n-th antidiagonal of A124976.

%t t[m_, n_] := t[m, n] = If[m == 1 || n == 1, 1,Sum[t[k, n], {k, m - 1}] * Sum[t[m, j], {j, n - 1}]];Plus @@@ Table[t[d + 1 - j, j], {d, 12}, {j, d}] (* _Ray Chandler_, Dec 11 2006 *)

%Y Cf. A124976.

%K easy,nonn

%O 1,2

%A _Leroy Quet_, Nov 23 2006

%E Extended by _Ray Chandler_, Dec 11 2006