A108441 - cp's OEIS frontend

A108441 Triangle read by rows: T(n,k) is 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 having k U=(1,2) steps among the steps leading to the first d step.

n	a(n)
0	1
1	1
2	1
3	3
4	6
5	1
6	15
7	39
8	11
9	1
10	97
11	284
12	100
13	16
14	1
15	721
16	2249
17	888
18	186
19	21
20	1
21	5827
22	18890
23	7977
24	1952
25	297
26	26
27	1
28	49759
29	165519
30	72991
31	19731
32	3601
33	433
34	31
35	1
36	441729
37	1496696
38	680096
39	196864
40	40586
41	5960
42	594
43	36
44	1
45	4035937
46	13865297
47	6439656

[1, 1, 1, 3, 6, 1, 15, 39, 11, 1, 97, 284, 100, 16, 1, 721, 2249, 888, 186, 21, 1, 5827, 18890, 7977, 1952, 297, 26, 1, 49759, 165519, 72991, 19731, 3601, 433, 31, 1, 441729, 1496696, 680096, 196864, 40586, 5960, 594, 36, 1, 4035937, 13865297, 6439656]

cp's OEIS Frontend

A108441 Triangle read by rows: T(n,k) is 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 having k U=(1,2) steps among the steps leading to the first d step.

Table of values

List of values