A366472 - cp's OEIS frontend

A366472 Irregular triangle read by rows: T(n,k) (n >= 1, k >= 1) = number of increasing geometric progressions in {1,2,3,...,n} of length k with rational ratio.

n	a(n)
1	1
2	2
3	1
4	3
5	3
6	4
7	6
8	1
9	5
10	10
11	1
12	6
13	15
14	1
15	7
16	21
17	1
18	8
19	28
20	2
21	1
22	9
23	36
24	4
25	1
26	10
27	45
28	4
29	1
30	11
31	55
32	4
33	1
34	12
35	66
36	5
37	1
38	13
39	78
40	5
41	1
42	14
43	91
44	5
45	1
46	15
47	105
48	5
49	1
50	16
51	120
52	8
53	2
54	1
55	17
56	136
57	8
58	2
59	1
60	18
61	153
62	10
63	2
64	1
65	19
66	171
67	10
68	2
69	1
70	20
71	190
72	11
73	2
74	1
75	21
76	210
77	11
78	2
79	1
80	22
81	231
82	11
83	2
84	1
85	23
86	253
87	11
88	2
89	1
90	24
91	276
92	12
93	3
94	1

[1, 2, 1, 3, 3, 4, 6, 1, 5, 10, 1, 6, 15, 1, 7, 21, 1, 8, 28, 2, 1, 9, 36, 4, 1, 10, 45, 4, 1, 11, 55, 4, 1, 12, 66, 5, 1, 13, 78, 5, 1, 14, 91, 5, 1, 15, 105, 5, 1, 16, 120, 8, 2, 1, 17, 136, 8, 2, 1, 18, 153, 10, 2, 1, 19, 171, 10, 2, 1, 20, 190, 11, 2, 1, 21, 210, 11, 2, 1, 22, 231, 11, 2, 1, 23, 253, 11, 2, 1, 24, 276, 12, 3, 1]

cp's OEIS Frontend

A366472 Irregular triangle read by rows: T(n,k) (n >= 1, k >= 1) = number of increasing geometric progressions in {1,2,3,...,n} of length k with rational ratio.

Table of values

List of values

n	a(n)
1	1
2	2
3	1
4	3
5	3
6	4
7	6
8	1
9	5
10	10
11	1
12	6
13	15
14	1
15	7
16	21
17	1
18	8
19	28
20	2
21	1
22	9
23	36
24	4
25	1
26	10
27	45
28	4
29	1
30	11
31	55
32	4
33	1
34	12
35	66
36	5
37	1
38	13
39	78
40	5
41	1
42	14
43	91
44	5
45	1
46	15
47	105
48	5
49	1
50	16
51	120
52	8
53	2
54	1
55	17
56	136
57	8
58	2
59	1
60	18
61	153
62	10
63	2
64	1
65	19
66	171
67	10
68	2
69	1
70	20
71	190
72	11
73	2
74	1
75	21
76	210
77	11
78	2
79	1
80	22
81	231
82	11
83	2
84	1
85	23
86	253
87	11
88	2
89	1
90	24
91	276
92	12
93	3
94	1

n	a(n)
1	1
2	2
3	1
4	3
5	3
6	4
7	6
8	1
9	5
10	10
11	1
12	6
13	15
14	1
15	7
16	21
17	1
18	8
19	28
20	2
21	1
22	9
23	36
24	4
25	1
26	10
27	45
28	4
29	1
30	11
31	55
32	4
33	1
34	12
35	66
36	5
37	1
38	13
39	78
40	5
41	1
42	14
43	91
44	5
45	1
46	15
47	105
48	5
49	1
50	16
51	120
52	8
53	2
54	1
55	17
56	136
57	8
58	2
59	1
60	18
61	153
62	10
63	2
64	1
65	19
66	171
67	10
68	2
69	1
70	20
71	190
72	11
73	2
74	1
75	21
76	210
77	11
78	2
79	1
80	22
81	231
82	11
83	2
84	1
85	23
86	253
87	11
88	2
89	1
90	24
91	276
92	12
93	3
94	1

n	a(n)
1	1
2	2
3	1
4	3
5	3
6	4
7	6
8	1
9	5
10	10
11	1
12	6
13	15
14	1
15	7
16	21
17	1
18	8
19	28
20	2
21	1
22	9
23	36
24	4
25	1
26	10
27	45
28	4
29	1
30	11
31	55
32	4
33	1
34	12
35	66
36	5
37	1
38	13
39	78
40	5
41	1
42	14
43	91
44	5
45	1
46	15
47	105
48	5
49	1
50	16
51	120
52	8
53	2
54	1
55	17
56	136
57	8
58	2
59	1
60	18
61	153
62	10
63	2
64	1
65	19
66	171
67	10
68	2
69	1
70	20
71	190
72	11
73	2
74	1
75	21
76	210
77	11
78	2
79	1
80	22
81	231
82	11
83	2
84	1
85	23
86	253
87	11
88	2
89	1
90	24
91	276
92	12
93	3
94	1