A067300 One third of third column of triangle A067298.

3, 12, 100, 1024, 11632, 140864, 1782080, 23273984, 311407360, 4246776832, 58812433408, 824868814848, 11692779565056, 167254617440256, 2411126992093184, 34994856661483520, 510941885186637824

Offset: 0

Author

Wolfdieter Lang, Feb 05 2002

Keywords

• nonn
• easy

Crossrefs

Cf. A067299 (second column), 8*A067301 (fourth column).

Formula

a(n)=A067298(n+2, 2)/3.

G.f.: ((1-4*x)*c(4*x)+2)/(1-2*x*c(4*x))^2, with c(x) is g.f. for A000108 (Catalan).