A027307 - cp's OEIS frontend

A027307 Number of paths from (0,0) to (3n,0) that stay in first quadrant (but may touch horizontal axis) and where each step is (2,1), (1,2) or (1,-1).

n	a(n)
0	1
1	2
2	10
3	66
4	498
5	4066
6	34970
7	312066
8	2862562
9	26824386
10	255680170
11	2471150402
12	24161357010
13	238552980386
14	2375085745978
15	23818652359682
16	240382621607874
17	2439561132029314
18	24881261270812490
19	254892699352950850

[1, 2, 10, 66, 498, 4066, 34970, 312066, 2862562, 26824386, 255680170, 2471150402, 24161357010, 238552980386, 2375085745978, 23818652359682, 240382621607874, 2439561132029314, 24881261270812490, 254892699352950850]

cp's OEIS Frontend

A027307 Number of paths from (0,0) to (3n,0) that stay in first quadrant (but may touch horizontal axis) and where each step is (2,1), (1,2) or (1,-1).

Table of values

List of values