A263569 - cp's OEIS frontend

A263569 Number of distinct prime divisors p of 2n such that lpf(2n - p) = p, where lpf = least prime factor (A020639).

n	a(n)
1	0
2	1
3	2
4	1
5	2
6	2
7	2
8	1
9	2
10	1
11	2
12	2
13	2
14	1
15	3
16	1
17	2
18	2
19	2
20	2
21	2
22	1
23	2
24	2
25	1
26	1
27	2
28	2
29	2
30	3
31	2
32	1
33	2
34	1
35	2
36	2
37	2
38	1
39	2
40	1
41	2
42	3
43	2
44	1
45	3
46	1
47	2
48	2
49	2
50	2
51	2
52	1
53	2
54	2
55	1
56	1
57	2
58	1
59	2
60	3
61	2
62	1
63	3
64	1
65	2
66	3
67	2
68	1
69	2
70	2
71	2
72	2
73	2
74	1
75	3
76	1
77	2
78	2
79	2
80	2
81	2
82	1
83	2
84	3
85	1
86	1
87	2
88	1
89	2
90	3
91	2
92	1
93	2
94	1
95	2
96	2
97	2
98	1
99	3
100	1
101	2
102	2
103	2
104	1
105	4

[0, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 2, 2, 3, 2, 1, 2, 1, 2, 2, 2, 1, 2, 1, 2, 3, 2, 1, 3, 1, 2, 2, 2, 2, 2, 1, 2, 2, 1, 1, 2, 1, 2, 3, 2, 1, 3, 1, 2, 3, 2, 1, 2, 2, 2, 2, 2, 1, 3, 1, 2, 2, 2, 2, 2, 1, 2, 3, 1, 1, 2, 1, 2, 3, 2, 1, 2, 1, 2, 2, 2, 1, 3, 1, 2, 2, 2, 1, 4]

cp's OEIS Frontend

A263569 Number of distinct prime divisors p of 2n such that lpf(2n - p) = p, where lpf = least prime factor (A020639).

Table of values

List of values

n	a(n)
1	0
2	1
3	2
4	1
5	2
6	2
7	2
8	1
9	2
10	1
11	2
12	2
13	2
14	1
15	3
16	1
17	2
18	2
19	2
20	2
21	2
22	1
23	2
24	2
25	1
26	1
27	2
28	2
29	2
30	3
31	2
32	1
33	2
34	1
35	2
36	2
37	2
38	1
39	2
40	1
41	2
42	3
43	2
44	1
45	3
46	1
47	2
48	2
49	2
50	2
51	2
52	1
53	2
54	2
55	1
56	1
57	2
58	1
59	2
60	3
61	2
62	1
63	3
64	1
65	2
66	3
67	2
68	1
69	2
70	2
71	2
72	2
73	2
74	1
75	3
76	1
77	2
78	2
79	2
80	2
81	2
82	1
83	2
84	3
85	1
86	1
87	2
88	1
89	2
90	3
91	2
92	1
93	2
94	1
95	2
96	2
97	2
98	1
99	3
100	1
101	2
102	2
103	2
104	1
105	4

n	a(n)
1	0
2	1
3	2
4	1
5	2
6	2
7	2
8	1
9	2
10	1
11	2
12	2
13	2
14	1
15	3
16	1
17	2
18	2
19	2
20	2
21	2
22	1
23	2
24	2
25	1
26	1
27	2
28	2
29	2
30	3
31	2
32	1
33	2
34	1
35	2
36	2
37	2
38	1
39	2
40	1
41	2
42	3
43	2
44	1
45	3
46	1
47	2
48	2
49	2
50	2
51	2
52	1
53	2
54	2
55	1
56	1
57	2
58	1
59	2
60	3
61	2
62	1
63	3
64	1
65	2
66	3
67	2
68	1
69	2
70	2
71	2
72	2
73	2
74	1
75	3
76	1
77	2
78	2
79	2
80	2
81	2
82	1
83	2
84	3
85	1
86	1
87	2
88	1
89	2
90	3
91	2
92	1
93	2
94	1
95	2
96	2
97	2
98	1
99	3
100	1
101	2
102	2
103	2
104	1
105	4

cp's OEIS Frontend

A263569 Number of distinct prime divisors p of 2*n such that lpf(2*n - p) = p, where lpf = least prime factor (A020639).

Table of values

List of values

A263569 Number of distinct prime divisors p of 2n such that lpf(2n - p) = p, where lpf = least prime factor (A020639).

n	a(n)
1	0
2	1
3	2
4	1
5	2
6	2
7	2
8	1
9	2
10	1
11	2
12	2
13	2
14	1
15	3
16	1
17	2
18	2
19	2
20	2
21	2
22	1
23	2
24	2
25	1
26	1
27	2
28	2
29	2
30	3
31	2
32	1
33	2
34	1
35	2
36	2
37	2
38	1
39	2
40	1
41	2
42	3
43	2
44	1
45	3
46	1
47	2
48	2
49	2
50	2
51	2
52	1
53	2
54	2
55	1
56	1
57	2
58	1
59	2
60	3
61	2
62	1
63	3
64	1
65	2
66	3
67	2
68	1
69	2
70	2
71	2
72	2
73	2
74	1
75	3
76	1
77	2
78	2
79	2
80	2
81	2
82	1
83	2
84	3
85	1
86	1
87	2
88	1
89	2
90	3
91	2
92	1
93	2
94	1
95	2
96	2
97	2
98	1
99	3
100	1
101	2
102	2
103	2
104	1
105	4