A180572 - cp's OEIS frontend

A180572 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the circular ladder P_2 X C_n (also called a prism), where P_2 is the path graph on 2 nodes and C_n is the cycle graph on n nodes.

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

[9, 6, 12, 12, 4, 15, 20, 10, 18, 24, 18, 6, 21, 28, 28, 14, 24, 32, 32, 24, 8, 27, 36, 36, 36, 18, 30, 40, 40, 40, 30, 10, 33, 44, 44, 44, 44, 22, 36, 48, 48, 48, 48, 36, 12, 39, 52, 52, 52, 52, 52, 26, 42, 56, 56, 56, 56, 56, 42, 14, 45, 60, 60, 60, 60, 60, 60, 30, 48, 64, 64]

cp's OEIS Frontend

A180572 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the circular ladder P_2 X C_n (also called a prism), where P_2 is the path graph on 2 nodes and C_n is the cycle graph on n nodes.

Table of values

List of values

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

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

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