A306440 - cp's OEIS frontend

A306440 Number of different ways of expressing 2n as (p - 1)(q - 1), where p < q are primes.

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

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

cp's OEIS Frontend

A306440 Number of different ways of expressing 2n as (p - 1)(q - 1), where p < q are primes.

Table of values

List of values

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

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

cp's OEIS Frontend

A306440 Number of different ways of expressing 2*n as (p - 1)*(q - 1), where p < q are primes.

Table of values

List of values

A306440 Number of different ways of expressing 2n as (p - 1)(q - 1), where p < q are primes.

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