0,2

a(n)=sum(C(k)*3^k, k=0..n), n>=0, with C(n):=A000108(n).

G.f.: c(3*x)/(1-x), where c(x):=(1-sqrt(1-4*x))/(2*x) is the o.g.f. of Catalan numbers A000108.

Fourth column (m=3) of triangle A112705.

Sequence in context: A083410 A052772 A052650 this_sequence A113717 A124563 A122704

Adjacent sequences: A112694 A112695 A112696 this_sequence A112698 A112699 A112700

nonn,easy

Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Oct 31 2005