A069902 - cp's OEIS frontend

A069902 Largest prime factor of n(n+1)/2, the n-th triangular number.

n	a(n)
1	1
2	3
3	3
4	5
5	5
6	7
7	7
8	3
9	5
10	11
11	11
12	13
13	13
14	7
15	5
16	17
17	17
18	19
19	19
20	7
21	11
22	23
23	23
24	5
25	13
26	13
27	7
28	29
29	29
30	31
31	31
32	11
33	17
34	17
35	7
36	37
37	37
38	19
39	13
40	41
41	41
42	43
43	43
44	11
45	23
46	47
47	47
48	7
49	7
50	17
51	17
52	53
53	53
54	11
55	11
56	19
57	29
58	59
59	59
60	61
61	61
62	31
63	7
64	13
65	13
66	67

[1, 3, 3, 5, 5, 7, 7, 3, 5, 11, 11, 13, 13, 7, 5, 17, 17, 19, 19, 7, 11, 23, 23, 5, 13, 13, 7, 29, 29, 31, 31, 11, 17, 17, 7, 37, 37, 19, 13, 41, 41, 43, 43, 11, 23, 47, 47, 7, 7, 17, 17, 53, 53, 11, 11, 19, 29, 59, 59, 61, 61, 31, 7, 13, 13, 67]

cp's OEIS Frontend

A069902 Largest prime factor of n(n+1)/2, the n-th triangular number.

Table of values

List of values

n	a(n)
1	1
2	3
3	3
4	5
5	5
6	7
7	7
8	3
9	5
10	11
11	11
12	13
13	13
14	7
15	5
16	17
17	17
18	19
19	19
20	7
21	11
22	23
23	23
24	5
25	13
26	13
27	7
28	29
29	29
30	31
31	31
32	11
33	17
34	17
35	7
36	37
37	37
38	19
39	13
40	41
41	41
42	43
43	43
44	11
45	23
46	47
47	47
48	7
49	7
50	17
51	17
52	53
53	53
54	11
55	11
56	19
57	29
58	59
59	59
60	61
61	61
62	31
63	7
64	13
65	13
66	67

n	a(n)
1	1
2	3
3	3
4	5
5	5
6	7
7	7
8	3
9	5
10	11
11	11
12	13
13	13
14	7
15	5
16	17
17	17
18	19
19	19
20	7
21	11
22	23
23	23
24	5
25	13
26	13
27	7
28	29
29	29
30	31
31	31
32	11
33	17
34	17
35	7
36	37
37	37
38	19
39	13
40	41
41	41
42	43
43	43
44	11
45	23
46	47
47	47
48	7
49	7
50	17
51	17
52	53
53	53
54	11
55	11
56	19
57	29
58	59
59	59
60	61
61	61
62	31
63	7
64	13
65	13
66	67

n	a(n)
1	1
2	3
3	3
4	5
5	5
6	7
7	7
8	3
9	5
10	11
11	11
12	13
13	13
14	7
15	5
16	17
17	17
18	19
19	19
20	7
21	11
22	23
23	23
24	5
25	13
26	13
27	7
28	29
29	29
30	31
31	31
32	11
33	17
34	17
35	7
36	37
37	37
38	19
39	13
40	41
41	41
42	43
43	43
44	11
45	23
46	47
47	47
48	7
49	7
50	17
51	17
52	53
53	53
54	11
55	11
56	19
57	29
58	59
59	59
60	61
61	61
62	31
63	7
64	13
65	13
66	67