A180570 - cp's OEIS frontend

A180570 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the graph \|/\/\/...\/_\|/ having n nodes on the horizontal path. The entries in row n are the coefficients of the Wiener polynomial of the graph.

n	a(n)
2	7
3	12
4	9
5	10
6	18
7	18
8	9
9	13
10	24
11	27
12	18
13	9
14	16
15	30
16	36
17	27
18	18
19	9
20	19
21	36
22	45
23	36
24	27
25	18
26	9
27	22
28	42
29	54
30	45
31	36
32	27
33	18
34	9
35	25
36	48
37	63
38	54
39	45
40	36
41	27
42	18
43	9
44	28
45	54
46	72
47	63
48	54
49	45
50	36
51	27
52	18
53	9
54	31
55	60
56	81
57	72
58	63
59	54
60	45
61	36
62	27
63	18
64	9
65	34
66	66
67	90
68	81
69	72
70	63
71	54
72	45
73	36
74	27

[7, 12, 9, 10, 18, 18, 9, 13, 24, 27, 18, 9, 16, 30, 36, 27, 18, 9, 19, 36, 45, 36, 27, 18, 9, 22, 42, 54, 45, 36, 27, 18, 9, 25, 48, 63, 54, 45, 36, 27, 18, 9, 28, 54, 72, 63, 54, 45, 36, 27, 18, 9, 31, 60, 81, 72, 63, 54, 45, 36, 27, 18, 9, 34, 66, 90, 81, 72, 63, 54, 45, 36, 27]

cp's OEIS Frontend

A180570 Triangle read by rows: T(n,k) is the number of unordered pairs of vertices at distance k in the graph \|/\/\/...\/_\|/ having n nodes on the horizontal path. The entries in row n are the coefficients of the Wiener polynomial of the graph.

Table of values

List of values

n	a(n)
2	7
3	12
4	9
5	10
6	18
7	18
8	9
9	13
10	24
11	27
12	18
13	9
14	16
15	30
16	36
17	27
18	18
19	9
20	19
21	36
22	45
23	36
24	27
25	18
26	9
27	22
28	42
29	54
30	45
31	36
32	27
33	18
34	9
35	25
36	48
37	63
38	54
39	45
40	36
41	27
42	18
43	9
44	28
45	54
46	72
47	63
48	54
49	45
50	36
51	27
52	18
53	9
54	31
55	60
56	81
57	72
58	63
59	54
60	45
61	36
62	27
63	18
64	9
65	34
66	66
67	90
68	81
69	72
70	63
71	54
72	45
73	36
74	27

n	a(n)
2	7
3	12
4	9
5	10
6	18
7	18
8	9
9	13
10	24
11	27
12	18
13	9
14	16
15	30
16	36
17	27
18	18
19	9
20	19
21	36
22	45
23	36
24	27
25	18
26	9
27	22
28	42
29	54
30	45
31	36
32	27
33	18
34	9
35	25
36	48
37	63
38	54
39	45
40	36
41	27
42	18
43	9
44	28
45	54
46	72
47	63
48	54
49	45
50	36
51	27
52	18
53	9
54	31
55	60
56	81
57	72
58	63
59	54
60	45
61	36
62	27
63	18
64	9
65	34
66	66
67	90
68	81
69	72
70	63
71	54
72	45
73	36
74	27

n	a(n)
2	7
3	12
4	9
5	10
6	18
7	18
8	9
9	13
10	24
11	27
12	18
13	9
14	16
15	30
16	36
17	27
18	18
19	9
20	19
21	36
22	45
23	36
24	27
25	18
26	9
27	22
28	42
29	54
30	45
31	36
32	27
33	18
34	9
35	25
36	48
37	63
38	54
39	45
40	36
41	27
42	18
43	9
44	28
45	54
46	72
47	63
48	54
49	45
50	36
51	27
52	18
53	9
54	31
55	60
56	81
57	72
58	63
59	54
60	45
61	36
62	27
63	18
64	9
65	34
66	66
67	90
68	81
69	72
70	63
71	54
72	45
73	36
74	27