A260648 - cp's OEIS frontend

A260648 Number of distinct prime divisors p of the n-th composite number c such that gpf(c - p) = p, where gpf = greatest prime factor (A006530).

n	a(n)
1	1
2	2
3	0
4	1
5	2
6	1
7	1
8	2
9	0
10	1
11	1
12	2
13	1
14	0
15	1
16	1
17	1
18	1
19	2
20	0
21	1
22	2
23	2
24	0
25	1
26	2
27	0
28	1
29	1
30	1
31	1
32	0
33	1
34	1
35	2
36	1
37	0
38	2
39	1
40	2
41	1
42	0
43	1
44	1
45	0
46	2
47	2
48	1
49	1
50	1
51	0
52	1
53	1
54	1
55	2
56	1
57	1
58	0
59	1
60	1
61	2
62	1
63	1
64	1
65	0
66	2
67	1
68	1
69	1
70	2
71	0
72	0
73	2
74	0
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	1
84	1
85	1
86	1
87	1
88	2
89	0
90	1
91	1
92	1
93	1
94	1
95	0
96	0
97	1
98	3

[1, 2, 0, 1, 2, 1, 1, 2, 0, 1, 1, 2, 1, 0, 1, 1, 1, 1, 2, 0, 1, 2, 2, 0, 1, 2, 0, 1, 1, 1, 1, 0, 1, 1, 2, 1, 0, 2, 1, 2, 1, 0, 1, 1, 0, 2, 2, 1, 1, 1, 0, 1, 1, 1, 2, 1, 1, 0, 1, 1, 2, 1, 1, 1, 0, 2, 1, 1, 1, 2, 0, 0, 2, 0, 1, 1, 2, 1, 0, 1, 2, 1, 1, 1, 1, 1, 1, 2, 0, 1, 1, 1, 1, 1, 0, 0, 1, 3]

cp's OEIS Frontend

A260648 Number of distinct prime divisors p of the n-th composite number c such that gpf(c - p) = p, where gpf = greatest prime factor (A006530).

Table of values

List of values

n	a(n)
1	1
2	2
3	0
4	1
5	2
6	1
7	1
8	2
9	0
10	1
11	1
12	2
13	1
14	0
15	1
16	1
17	1
18	1
19	2
20	0
21	1
22	2
23	2
24	0
25	1
26	2
27	0
28	1
29	1
30	1
31	1
32	0
33	1
34	1
35	2
36	1
37	0
38	2
39	1
40	2
41	1
42	0
43	1
44	1
45	0
46	2
47	2
48	1
49	1
50	1
51	0
52	1
53	1
54	1
55	2
56	1
57	1
58	0
59	1
60	1
61	2
62	1
63	1
64	1
65	0
66	2
67	1
68	1
69	1
70	2
71	0
72	0
73	2
74	0
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	1
84	1
85	1
86	1
87	1
88	2
89	0
90	1
91	1
92	1
93	1
94	1
95	0
96	0
97	1
98	3

n	a(n)
1	1
2	2
3	0
4	1
5	2
6	1
7	1
8	2
9	0
10	1
11	1
12	2
13	1
14	0
15	1
16	1
17	1
18	1
19	2
20	0
21	1
22	2
23	2
24	0
25	1
26	2
27	0
28	1
29	1
30	1
31	1
32	0
33	1
34	1
35	2
36	1
37	0
38	2
39	1
40	2
41	1
42	0
43	1
44	1
45	0
46	2
47	2
48	1
49	1
50	1
51	0
52	1
53	1
54	1
55	2
56	1
57	1
58	0
59	1
60	1
61	2
62	1
63	1
64	1
65	0
66	2
67	1
68	1
69	1
70	2
71	0
72	0
73	2
74	0
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	1
84	1
85	1
86	1
87	1
88	2
89	0
90	1
91	1
92	1
93	1
94	1
95	0
96	0
97	1
98	3

n	a(n)
1	1
2	2
3	0
4	1
5	2
6	1
7	1
8	2
9	0
10	1
11	1
12	2
13	1
14	0
15	1
16	1
17	1
18	1
19	2
20	0
21	1
22	2
23	2
24	0
25	1
26	2
27	0
28	1
29	1
30	1
31	1
32	0
33	1
34	1
35	2
36	1
37	0
38	2
39	1
40	2
41	1
42	0
43	1
44	1
45	0
46	2
47	2
48	1
49	1
50	1
51	0
52	1
53	1
54	1
55	2
56	1
57	1
58	0
59	1
60	1
61	2
62	1
63	1
64	1
65	0
66	2
67	1
68	1
69	1
70	2
71	0
72	0
73	2
74	0
75	1
76	1
77	2
78	1
79	0
80	1
81	2
82	1
83	1
84	1
85	1
86	1
87	1
88	2
89	0
90	1
91	1
92	1
93	1
94	1
95	0
96	0
97	1
98	3