A278961 - cp's OEIS frontend

A278961 Triangle read by rows: row n consists of k, 1<=k<=n, such that binomial(n,k) is divisible by gcd(n,k).

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

[1, 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 5, 1, 2, 3, 4, 5, 6, 1, 2, 3, 5, 6, 7, 1, 2, 3, 4, 5, 6, 7, 8, 1, 3, 4, 6, 7, 9, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 5, 6, 7, 10, 11, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 1, 3, 5, 9, 11, 13, 1, 2, 4, 7, 8, 11, 13, 14, 1, 2]

cp's OEIS Frontend

A278961 Triangle read by rows: row n consists of k, 1<=k<=n, such that binomial(n,k) is divisible by gcd(n,k).

Table of values

List of values

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

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

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