A227997 - cp's OEIS frontend

A227997 Triangular array read by rows. T(n,k) is the number of square lattice walks that start and end at the origin after 2n steps having k primitive loops; n>=1, 1<=k<=n.

n	a(n)
1	4
2	20
3	16
4	176
5	160
6	64
7	1876
8	1808
9	960
10	256
11	22064
12	22048
13	13248
14	5120
15	1024
16	275568
17	282528
18	182528
19	83456
20	25600
21	4096
22	3584064
23	3747456
24	2542464
25	1284096
26	481280
27	122880
28	16384
29	47995476
30	50981136
31	35851968
32	19365120
33	8186880
34	2617344
35	573440
36	65536
37	657037232
38	707110432
39	511288256
40	290053120
41	133084160
42	48799744
43	13647872
44	2621440
45	262144
46	9150655216
47	9958458656
48	7363711104
49	4338317824
50	2113592320
51	851398656
52	276856832
53	68943872
54	11796480
55	1048576

[4, 20, 16, 176, 160, 64, 1876, 1808, 960, 256, 22064, 22048, 13248, 5120, 1024, 275568, 282528, 182528, 83456, 25600, 4096, 3584064, 3747456, 2542464, 1284096, 481280, 122880, 16384, 47995476, 50981136, 35851968, 19365120, 8186880, 2617344, 573440, 65536, 657037232, 707110432, 511288256, 290053120, 133084160, 48799744, 13647872, 2621440, 262144, 9150655216, 9958458656, 7363711104, 4338317824, 2113592320, 851398656, 276856832, 68943872, 11796480, 1048576]

cp's OEIS Frontend

A227997 Triangular array read by rows. T(n,k) is the number of square lattice walks that start and end at the origin after 2n steps having k primitive loops; n>=1, 1<=k<=n.

Table of values

List of values