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

4,1

Links

Table of n, a(n) for n=4..26.

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).

Crossrefs

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

Sequence in context: A328259 A005052 A057344 * A245428 A307307 A377068

Adjacent sequences: A115131 A115132 A115133 * A115135 A115136 A115137

Keyword

nonn,easy

Author

Wolfdieter Lang, Jan 13 2006

Status

approved