A076605 - cp's OEIS frontend

A076605 Largest prime divisor of n^2 - 1.

n	a(n)
2	3
3	2
4	5
5	3
6	7
7	3
8	7
9	5
10	11
11	5
12	13
13	7
14	13
15	7
16	17
17	3
18	19
19	5
20	19
21	11
22	23
23	11
24	23
25	13
26	5
27	13
28	29
29	7
30	31
31	5
32	31
33	17
34	11
35	17
36	37
37	19
38	37
39	19
40	41
41	7
42	43
43	11
44	43
45	23
46	47
47	23
48	47
49	5
50	17
51	13
52	53
53	13
54	53
55	7
56	19
57	29
58	59
59	29
60	61
61	31
62	61
63	31
64	13
65	11
66	67
67	17
68	67
69	17
70	71
71	7

[3, 2, 5, 3, 7, 3, 7, 5, 11, 5, 13, 7, 13, 7, 17, 3, 19, 5, 19, 11, 23, 11, 23, 13, 5, 13, 29, 7, 31, 5, 31, 17, 11, 17, 37, 19, 37, 19, 41, 7, 43, 11, 43, 23, 47, 23, 47, 5, 17, 13, 53, 13, 53, 7, 19, 29, 59, 29, 61, 31, 61, 31, 13, 11, 67, 17, 67, 17, 71, 7]

cp's OEIS Frontend

A076605 Largest prime divisor of n^2 - 1.

Table of values

List of values

n	a(n)
2	3
3	2
4	5
5	3
6	7
7	3
8	7
9	5
10	11
11	5
12	13
13	7
14	13
15	7
16	17
17	3
18	19
19	5
20	19
21	11
22	23
23	11
24	23
25	13
26	5
27	13
28	29
29	7
30	31
31	5
32	31
33	17
34	11
35	17
36	37
37	19
38	37
39	19
40	41
41	7
42	43
43	11
44	43
45	23
46	47
47	23
48	47
49	5
50	17
51	13
52	53
53	13
54	53
55	7
56	19
57	29
58	59
59	29
60	61
61	31
62	61
63	31
64	13
65	11
66	67
67	17
68	67
69	17
70	71
71	7

n	a(n)
2	3
3	2
4	5
5	3
6	7
7	3
8	7
9	5
10	11
11	5
12	13
13	7
14	13
15	7
16	17
17	3
18	19
19	5
20	19
21	11
22	23
23	11
24	23
25	13
26	5
27	13
28	29
29	7
30	31
31	5
32	31
33	17
34	11
35	17
36	37
37	19
38	37
39	19
40	41
41	7
42	43
43	11
44	43
45	23
46	47
47	23
48	47
49	5
50	17
51	13
52	53
53	13
54	53
55	7
56	19
57	29
58	59
59	29
60	61
61	31
62	61
63	31
64	13
65	11
66	67
67	17
68	67
69	17
70	71
71	7

n	a(n)
2	3
3	2
4	5
5	3
6	7
7	3
8	7
9	5
10	11
11	5
12	13
13	7
14	13
15	7
16	17
17	3
18	19
19	5
20	19
21	11
22	23
23	11
24	23
25	13
26	5
27	13
28	29
29	7
30	31
31	5
32	31
33	17
34	11
35	17
36	37
37	19
38	37
39	19
40	41
41	7
42	43
43	11
44	43
45	23
46	47
47	23
48	47
49	5
50	17
51	13
52	53
53	13
54	53
55	7
56	19
57	29
58	59
59	29
60	61
61	31
62	61
63	31
64	13
65	11
66	67
67	17
68	67
69	17
70	71
71	7