A010683 - cp's OEIS frontend

A010683 Let S(x,y) = number of lattice paths from (0,0) to (x,y) that use the step set { (0,1), (1,0), (2,0), (3,0), ...} and never pass below y = x. Sequence gives S(n-1,n) = number of 'Schröder' trees with n+1 leaves and root of degree 2.

n	a(n)
0	1
1	2
2	7
3	28
4	121
5	550
6	2591
7	12536
8	61921
9	310954
10	1582791
11	8147796
12	42344121
13	221866446
14	1170747519
15	6216189936
16	33186295681
17	178034219986
18	959260792775
19	5188835909516
20	28167068630713
21	153395382655222

[1, 2, 7, 28, 121, 550, 2591, 12536, 61921, 310954, 1582791, 8147796, 42344121, 221866446, 1170747519, 6216189936, 33186295681, 178034219986, 959260792775, 5188835909516, 28167068630713, 153395382655222]

cp's OEIS Frontend

A010683 Let S(x,y) = number of lattice paths from (0,0) to (x,y) that use the step set { (0,1), (1,0), (2,0), (3,0), ...} and never pass below y = x. Sequence gives S(n-1,n) = number of 'Schröder' trees with n+1 leaves and root of degree 2.

Table of values

List of values