A193990 - cp's OEIS frontend

A193990 Number of distinct prime factors <= n of binomial(2*n,n).

n	a(n)
1	0
2	1
3	1
4	1
5	2
6	2
7	2
8	3
9	2
10	1
11	3
12	2
13	3
14	3
15	3
16	3
17	4
18	5
19	5
20	6
21	5
22	4
23	4
24	4
25	4
26	4
27	3
28	5
29	7
30	5
31	5
32	6
33	7
34	6
35	6
36	5
37	5
38	6
39	5
40	5
41	6
42	6
43	7
44	7
45	7
46	7
47	8
48	9
49	8
50	8
51	7
52	6
53	8
54	8
55	6
56	6
57	5
58	6
59	7
60	8
61	9
62	9
63	9
64	9
65	9
66	9
67	11
68	10
69	9
70	8
71	9
72	10
73	11
74	11
75	11
76	10
77	11
78	11
79	11
80	12
81	12
82	11

[0, 1, 1, 1, 2, 2, 2, 3, 2, 1, 3, 2, 3, 3, 3, 3, 4, 5, 5, 6, 5, 4, 4, 4, 4, 4, 3, 5, 7, 5, 5, 6, 7, 6, 6, 5, 5, 6, 5, 5, 6, 6, 7, 7, 7, 7, 8, 9, 8, 8, 7, 6, 8, 8, 6, 6, 5, 6, 7, 8, 9, 9, 9, 9, 9, 9, 11, 10, 9, 8, 9, 10, 11, 11, 11, 10, 11, 11, 11, 12, 12, 11]

cp's OEIS Frontend

A193990 Number of distinct prime factors <= n of binomial(2*n,n).

Table of values

List of values

n	a(n)
1	0
2	1
3	1
4	1
5	2
6	2
7	2
8	3
9	2
10	1
11	3
12	2
13	3
14	3
15	3
16	3
17	4
18	5
19	5
20	6
21	5
22	4
23	4
24	4
25	4
26	4
27	3
28	5
29	7
30	5
31	5
32	6
33	7
34	6
35	6
36	5
37	5
38	6
39	5
40	5
41	6
42	6
43	7
44	7
45	7
46	7
47	8
48	9
49	8
50	8
51	7
52	6
53	8
54	8
55	6
56	6
57	5
58	6
59	7
60	8
61	9
62	9
63	9
64	9
65	9
66	9
67	11
68	10
69	9
70	8
71	9
72	10
73	11
74	11
75	11
76	10
77	11
78	11
79	11
80	12
81	12
82	11

n	a(n)
1	0
2	1
3	1
4	1
5	2
6	2
7	2
8	3
9	2
10	1
11	3
12	2
13	3
14	3
15	3
16	3
17	4
18	5
19	5
20	6
21	5
22	4
23	4
24	4
25	4
26	4
27	3
28	5
29	7
30	5
31	5
32	6
33	7
34	6
35	6
36	5
37	5
38	6
39	5
40	5
41	6
42	6
43	7
44	7
45	7
46	7
47	8
48	9
49	8
50	8
51	7
52	6
53	8
54	8
55	6
56	6
57	5
58	6
59	7
60	8
61	9
62	9
63	9
64	9
65	9
66	9
67	11
68	10
69	9
70	8
71	9
72	10
73	11
74	11
75	11
76	10
77	11
78	11
79	11
80	12
81	12
82	11

n	a(n)
1	0
2	1
3	1
4	1
5	2
6	2
7	2
8	3
9	2
10	1
11	3
12	2
13	3
14	3
15	3
16	3
17	4
18	5
19	5
20	6
21	5
22	4
23	4
24	4
25	4
26	4
27	3
28	5
29	7
30	5
31	5
32	6
33	7
34	6
35	6
36	5
37	5
38	6
39	5
40	5
41	6
42	6
43	7
44	7
45	7
46	7
47	8
48	9
49	8
50	8
51	7
52	6
53	8
54	8
55	6
56	6
57	5
58	6
59	7
60	8
61	9
62	9
63	9
64	9
65	9
66	9
67	11
68	10
69	9
70	8
71	9
72	10
73	11
74	11
75	11
76	10
77	11
78	11
79	11
80	12
81	12
82	11