Number of steps in all Schroeder paths (i.e. consisting of steps U=(1,1), D=(1,-1),H=(2,0) and never going below the x-axis) from (0,0) to (2n,0).
3, 19, 107, 591, 3259, 18019, 99987, 556831, 3111347, 17436915, 97981179
1 seqfan posts
Tue Sep 13 03:59:00 CEST 2011 [seqfan] Flat steps in Schroeder paths that are not the first step