A230662 - cp's OEIS frontend

A230662 Number of lattice paths from (0,0) to (n,n) that do not go below the x-axis or above the diagonal x=y and consist of steps u=(1,1), U=(1,2), d=(1,-1), D=(1,-2) and H=(1,0).

n	a(n)
0	1
1	1
2	2
3	4
4	10
5	26
6	74
7	218
8	668
9	2096
10	6726
11	21946
12	72666
13	243504
14	824528
15	2816854
16	9698520
17	33620626
18	117254340
19	411135452
20	1448544666
21	5125796448
22	18209367238
23	64919822556
24	232206203152
25	833040115596
26	2996741699470
27	10807658186756
28	39068847237770

[1, 1, 2, 4, 10, 26, 74, 218, 668, 2096, 6726, 21946, 72666, 243504, 824528, 2816854, 9698520, 33620626, 117254340, 411135452, 1448544666, 5125796448, 18209367238, 64919822556, 232206203152, 833040115596, 2996741699470, 10807658186756, 39068847237770]

cp's OEIS Frontend

A230662 Number of lattice paths from (0,0) to (n,n) that do not go below the x-axis or above the diagonal x=y and consist of steps u=(1,1), U=(1,2), d=(1,-1), D=(1,-2) and H=(1,0).

Table of values

List of values