9382230

Appears in sequences

• a(n) = 3^n*Catalan(n).at n=8A005159
• Riordan array (1, x*c(3x)), c(x) the g.f. of A000108.at n=46A110518
• Number of walks within N^2 (the first quadrant of Z^2) starting at (0,0), ending on the vertical axis and consisting of 2 n steps taken from {(-1, -1), (-1, 0), (-1, 1), (1, 1)}.at n=8A151383
• G.f.: A(x) = 1 + x*exp( Sum_{k>=1} [A(-(-1)^k*x) - 1]^k/k ).at n=18A156909