A220878 Number of Catalan M-paths.

1, 2, 11, 75, 578, 4791, 41657, 374728, 3458073, 32553979, 311399612, 3018079529, 29573648337, 292494535982, 2916080902215, 29274765251531, 295683573477358, 3002574533715331, 30636334463337153, 313935121354840276, 3229378471937953501, 33336180648639258723

Offset

0,2

Links

Table of n, a(n) for n=0..21.

J. P. S. Kung and A. de Mier, Catalan lattice paths with rook, bishop and spider steps, Journal of Combinatorial Theory, Series A 120 (2013) 379-389.

Formula

Kung and de Mier give a g.f.

Maple

g := (3*t^2-t-1+sqrt(1-14*t+35*t^2-30*t^3+9*t^4))/4/t/(3*t-2) ;
taylor(%, t=0, 40) ;
seq(coeftayl(%, t=0, n), n=0..39) ; # R. J. Mathar, Jan 30 2013

Crossrefs

Sequence in context: A309146 A198088 A112894 * A049363 A055085 A354298

Adjacent sequences: A220875 A220876 A220877 * A220879 A220880 A220881

Keyword

nonn

Author

N. J. A. Sloane, Dec 27 2012

Status

approved