A143370 - cp's OEIS frontend

A143370 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the grid P_2 x P_n (1 <= k <= n). P_m is the path graph on m vertices.

n	a(n)
1	1
2	4
3	2
4	7
5	6
6	2
7	10
8	10
9	6
10	2
11	13
12	14
13	10
14	6
15	2
16	16
17	18
18	14
19	10
20	6
21	2
22	19
23	22
24	18
25	14
26	10
27	6
28	2
29	22
30	26
31	22
32	18
33	14
34	10
35	6
36	2
37	25
38	30
39	26
40	22
41	18
42	14
43	10
44	6
45	2
46	28
47	34
48	30
49	26
50	22
51	18
52	14
53	10
54	6
55	2
56	31
57	38
58	34
59	30
60	26
61	22
62	18
63	14
64	10
65	6
66	2
67	34
68	42
69	38
70	34
71	30
72	26
73	22
74	18
75	14
76	10
77	6
78	2

[1, 4, 2, 7, 6, 2, 10, 10, 6, 2, 13, 14, 10, 6, 2, 16, 18, 14, 10, 6, 2, 19, 22, 18, 14, 10, 6, 2, 22, 26, 22, 18, 14, 10, 6, 2, 25, 30, 26, 22, 18, 14, 10, 6, 2, 28, 34, 30, 26, 22, 18, 14, 10, 6, 2, 31, 38, 34, 30, 26, 22, 18, 14, 10, 6, 2, 34, 42, 38, 34, 30, 26, 22, 18, 14, 10, 6, 2]

cp's OEIS Frontend

A143370 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the grid P_2 x P_n (1 <= k <= n). P_m is the path graph on m vertices.

Table of values

List of values

n	a(n)
1	1
2	4
3	2
4	7
5	6
6	2
7	10
8	10
9	6
10	2
11	13
12	14
13	10
14	6
15	2
16	16
17	18
18	14
19	10
20	6
21	2
22	19
23	22
24	18
25	14
26	10
27	6
28	2
29	22
30	26
31	22
32	18
33	14
34	10
35	6
36	2
37	25
38	30
39	26
40	22
41	18
42	14
43	10
44	6
45	2
46	28
47	34
48	30
49	26
50	22
51	18
52	14
53	10
54	6
55	2
56	31
57	38
58	34
59	30
60	26
61	22
62	18
63	14
64	10
65	6
66	2
67	34
68	42
69	38
70	34
71	30
72	26
73	22
74	18
75	14
76	10
77	6
78	2

n	a(n)
1	1
2	4
3	2
4	7
5	6
6	2
7	10
8	10
9	6
10	2
11	13
12	14
13	10
14	6
15	2
16	16
17	18
18	14
19	10
20	6
21	2
22	19
23	22
24	18
25	14
26	10
27	6
28	2
29	22
30	26
31	22
32	18
33	14
34	10
35	6
36	2
37	25
38	30
39	26
40	22
41	18
42	14
43	10
44	6
45	2
46	28
47	34
48	30
49	26
50	22
51	18
52	14
53	10
54	6
55	2
56	31
57	38
58	34
59	30
60	26
61	22
62	18
63	14
64	10
65	6
66	2
67	34
68	42
69	38
70	34
71	30
72	26
73	22
74	18
75	14
76	10
77	6
78	2

n	a(n)
1	1
2	4
3	2
4	7
5	6
6	2
7	10
8	10
9	6
10	2
11	13
12	14
13	10
14	6
15	2
16	16
17	18
18	14
19	10
20	6
21	2
22	19
23	22
24	18
25	14
26	10
27	6
28	2
29	22
30	26
31	22
32	18
33	14
34	10
35	6
36	2
37	25
38	30
39	26
40	22
41	18
42	14
43	10
44	6
45	2
46	28
47	34
48	30
49	26
50	22
51	18
52	14
53	10
54	6
55	2
56	31
57	38
58	34
59	30
60	26
61	22
62	18
63	14
64	10
65	6
66	2
67	34
68	42
69	38
70	34
71	30
72	26
73	22
74	18
75	14
76	10
77	6
78	2