A027307

Sequences linked to this entry ?

• A108426: Triangle read by rows: T(n,k) is number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting … match row sums
  1 · 1, 1 · 3, 5, 2 · 12, 28, 21, 5 … Σ 1, 2, 10, 66, 498, 4066, 34970, 312066, …
  (−∞, 0)nonnegative
• A104978: Triangle read by rows, where the g.f. satisfies A(x, y) = 1 + x*A(x, y)^2 + x*y*A(x, y)^3. match row sums
  1 · 1, 1 · 2, 5, 3 · 5, 21, 28, 12 … Σ 1, 2, 10, 66, 498, 4066, 34970, 312066, …
  (−∞, 0)nonnegative