A175903 - cp's OEIS frontend

A175903 Numbers n such that there is another number k such that n^2-1 and k^2-1 have the same set of prime factors.

n	a(n)
1	4
2	5
3	7
4	11
5	13
6	17
7	19
8	23
9	25
10	26
11	29
12	31
13	34
14	35
15	37
16	41
17	43
18	49
19	51
20	53
21	55
22	56
23	59
24	61
25	65
26	67
27	71
28	76
29	79
30	81
31	83
32	89
33	91
34	92
35	97
36	101
37	109
38	111
39	113
40	125
41	127
42	129
43	131
44	139
45	149
46	151
47	155
48	161
49	169
50	179
51	181
52	187
53	191
54	197
55	199
56	209
57	223
58	235
59	239
60	241
61	251

[4, 5, 7, 11, 13, 17, 19, 23, 25, 26, 29, 31, 34, 35, 37, 41, 43, 49, 51, 53, 55, 56, 59, 61, 65, 67, 71, 76, 79, 81, 83, 89, 91, 92, 97, 101, 109, 111, 113, 125, 127, 129, 131, 139, 149, 151, 155, 161, 169, 179, 181, 187, 191, 197, 199, 209, 223, 235, 239, 241, 251]

cp's OEIS Frontend

A175903 Numbers n such that there is another number k such that n^2-1 and k^2-1 have the same set of prime factors.

Table of values

List of values

n	a(n)
1	4
2	5
3	7
4	11
5	13
6	17
7	19
8	23
9	25
10	26
11	29
12	31
13	34
14	35
15	37
16	41
17	43
18	49
19	51
20	53
21	55
22	56
23	59
24	61
25	65
26	67
27	71
28	76
29	79
30	81
31	83
32	89
33	91
34	92
35	97
36	101
37	109
38	111
39	113
40	125
41	127
42	129
43	131
44	139
45	149
46	151
47	155
48	161
49	169
50	179
51	181
52	187
53	191
54	197
55	199
56	209
57	223
58	235
59	239
60	241
61	251

n	a(n)
1	4
2	5
3	7
4	11
5	13
6	17
7	19
8	23
9	25
10	26
11	29
12	31
13	34
14	35
15	37
16	41
17	43
18	49
19	51
20	53
21	55
22	56
23	59
24	61
25	65
26	67
27	71
28	76
29	79
30	81
31	83
32	89
33	91
34	92
35	97
36	101
37	109
38	111
39	113
40	125
41	127
42	129
43	131
44	139
45	149
46	151
47	155
48	161
49	169
50	179
51	181
52	187
53	191
54	197
55	199
56	209
57	223
58	235
59	239
60	241
61	251

n	a(n)
1	4
2	5
3	7
4	11
5	13
6	17
7	19
8	23
9	25
10	26
11	29
12	31
13	34
14	35
15	37
16	41
17	43
18	49
19	51
20	53
21	55
22	56
23	59
24	61
25	65
26	67
27	71
28	76
29	79
30	81
31	83
32	89
33	91
34	92
35	97
36	101
37	109
38	111
39	113
40	125
41	127
42	129
43	131
44	139
45	149
46	151
47	155
48	161
49	169
50	179
51	181
52	187
53	191
54	197
55	199
56	209
57	223
58	235
59	239
60	241
61	251