A320875 - cp's OEIS frontend

A320875 Least d > 0 such that both Q = M + 2d and R = M + (M^2-1)/(Q-M) are prime, where M = 2^n - 1 = A000225(n), or 0 if there is no such d.

n	a(n)
1	0
2	1
3	2
4	1
5	3
6	8
7	2
8	0
9	6
10	4
11	66
12	16
13	20
14	0
15	6
16	1
17	2720
18	0
19	32
20	0
21	164
22	8
23	0
24	524288
25	153
26	3573184
27	2097152
28	7354396
29	19436
30	4517888
31	672
32	0
33	174080
34	0
35	262146
36	1984
37	48
38	0
39	4194296
40	79
41	30720
42	128
43	1825866
44	4188889
45	194396
46	27227248
47	0
48	16384
49	723
50	0
51	265227072
52	22771712
53	13982720
54	134217728
55	59885796
56	587144
57	19436
58	0
59	17179869152
60	8388608

[0, 1, 2, 1, 3, 8, 2, 0, 6, 4, 66, 16, 20, 0, 6, 1, 2720, 0, 32, 0, 164, 8, 0, 524288, 153, 3573184, 2097152, 7354396, 19436, 4517888, 672, 0, 174080, 0, 262146, 1984, 48, 0, 4194296, 79, 30720, 128, 1825866, 4188889, 194396, 27227248, 0, 16384, 723, 0, 265227072, 22771712, 13982720, 134217728, 59885796, 587144, 19436, 0, 17179869152, 8388608]

cp's OEIS Frontend

A320875 Least d > 0 such that both Q = M + 2d and R = M + (M^2-1)/(Q-M) are prime, where M = 2^n - 1 = A000225(n), or 0 if there is no such d.

Table of values

List of values