A114693 - cp's OEIS frontend

A114693 Number of returns to the x-axis in all hill-free Schroeder paths of length 2n+4. A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1.

n	a(n)
0	2
1	10
2	48
3	232
4	1138
5	5666
6	28592
7	145984
8	752978
9	3918282
10	20547456
11	108482952
12	576187554
13	3076640898
14	16506527392
15	88938911296
16	481067145826
17	2611212958154
18	14218923060752
19	77653486423528
20	425227486222482

[2, 10, 48, 232, 1138, 5666, 28592, 145984, 752978, 3918282, 20547456, 108482952, 576187554, 3076640898, 16506527392, 88938911296, 481067145826, 2611212958154, 14218923060752, 77653486423528, 425227486222482]

cp's OEIS Frontend

A114693 Number of returns to the x-axis in all hill-free Schroeder paths of length 2n+4. A Schroeder path of length 2n is a lattice path from (0,0) to (2n,0) consisting of U=(1,1), D=(1,-1) and H=(2,0) steps and never going below the x-axis. A hill is a peak at height 1.

Table of values

List of values