A108432 - cp's OEIS frontend

A108432 Number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1),U=(1,2), or d=(1,-1) and have no hills (a hill is either a ud or a Udd starting at the x-axis).

n	a(n)
0	1
1	0
2	6
3	34
4	274
5	2266
6	19738
7	177642
8	1640050
9	15445690
10	147813706
11	1433309194
12	14052298690
13	139063589370
14	1387288675002
15	13936344557354
16	140859338668306
17	1431424362057018
18	14616361066692778
19	149892742974500042
20	1543146417012350050
21	15942622531081651578

[1, 0, 6, 34, 274, 2266, 19738, 177642, 1640050, 15445690, 147813706, 1433309194, 14052298690, 139063589370, 1387288675002, 13936344557354, 140859338668306, 1431424362057018, 14616361066692778, 149892742974500042, 1543146417012350050, 15942622531081651578]

cp's OEIS Frontend

A108432 Number of paths from (0,0) to (3n,0) that stay in the first quadrant (but may touch the horizontal axis), consisting of steps u=(2,1),U=(1,2), or d=(1,-1) and have no hills (a hill is either a ud or a Udd starting at the x-axis).

Table of values

List of values