A068218 - cp's OEIS frontend

A068218 Triangle of numbers of square lattice walks that start and end at origin after 2k steps and contain exactly r steps to the east, not touching origin at intermediate stages.

n	a(n)
0	1
1	2
2	2
3	2
4	16
5	2
6	4
7	84
8	84
9	4
10	10
11	400
12	1056
13	400
14	10
15	28
16	1820
17	9184
18	9184
19	1820
20	28
21	84
22	8064
23	66276
24	126720
25	66276
26	8064
27	84
28	264
29	35112
30	426888
31	1329768
32	1329768
33	426888
34	35112
35	264
36	858
37	151008
38	2546544
39	11737440
40	19123776
41	11737440

[1, 2, 2, 2, 16, 2, 4, 84, 84, 4, 10, 400, 1056, 400, 10, 28, 1820, 9184, 9184, 1820, 28, 84, 8064, 66276, 126720, 66276, 8064, 84, 264, 35112, 426888, 1329768, 1329768, 426888, 35112, 264, 858, 151008, 2546544, 11737440, 19123776, 11737440]

cp's OEIS Frontend

A068218 Triangle of numbers of square lattice walks that start and end at origin after 2k steps and contain exactly r steps to the east, not touching origin at intermediate stages.

Table of values

List of values