A124066 a(n) = the sum of the terms in the n-th antidiagonal of A124976.

1, 2, 3, 6, 19, 138, 5555, 5661606, 8017014805939, 549978189515061145367082, 75619002235584922846322716556474301506401613843, 615505010930370584284868847397460604890896977173300806488671348925702765535678512305286

Offset

1,2

Links

Table of n, a(n) for n=1..12.

Mathematica

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 *)

Crossrefs

Cf. A124976.

Sequence in context: A075633 A141048 A326030 * A319204 A093447 A321203

Adjacent sequences: A124063 A124064 A124065 * A124067 A124068 A124069

Keyword

easy,nonn

Author

Leroy Quet, Nov 23 2006

Extensions

Extended by Ray Chandler, Dec 11 2006

Status

approved