A115134 Third diagonal sequence of triangle A115127.

10, 30, 95, 311, 1043, 3564, 12363, 43420, 154088, 551684, 1990326, 7228417, 26405725, 96961560, 357688755, 1324982160, 4926502020, 18379785300, 68783559810, 258141170430, 971310800694, 3663524817768, 13848466284350

Offset: 4

Author

Wolfdieter Lang, Jan 13 2006

Keywords

• nonn
• easy

Crossrefs

Cf. A071726 (second diagonal of A115127 for n>=3 with g.f. -(1+x+3*x^2)+(1+x^2)*c(x)).

Formula

G.f. -(1+x^2+4*x^3) + (1-x+x^3)*c(x) with the g.f. c(x):=(1-sqrt(1-4*x))/(2*x) of A000108 (Catalan).