A067324 Third column of triangle A067323.

2, 7, 23, 76, 255, 869, 3003, 10504, 37128, 132430, 476102, 1723528, 6277505, 22988385, 84592275, 312636240, 1159979700, 4319218530, 16134883410, 60452176200, 227110782990, 855361970034, 3228982640478

Offset

0,1

Comments

Also third diagonal of triangle A028364.

Links

Table of n, a(n) for n=0..22.

Formula

a(n)= A067323(n+2, 2)= C(n+3)-(C(n+2)+C(n+1)), C(n) := A000108(n) (Catalan).

G.f.: (c(x)^3)*(1+c(x)), with c(x) g.f. of A000108 (Catalan).

Crossrefs

Cf. A000245 (second column).

Sequence in context: A042575 A256030 A052924 * A047062 A292231 A292232

Adjacent sequences: A067321 A067322 A067323 * A067325 A067326 A067327

Keyword

nonn,easy

Author

Wolfdieter Lang, Feb 05 2002

Status

approved