A125769 - cp's OEIS frontend

A125769 a(n) is the least number j such that j*T_k +/- 1 is n-th prime for some k-th triangular number.

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

[1, 2, 1, 1, 1, 2, 3, 2, 4, 1, 2, 1, 2, 2, 8, 9, 4, 4, 1, 2, 2, 1, 3, 2, 16, 10, 17, 3, 2, 4, 6, 2, 1, 5, 10, 10, 2, 27, 6, 29, 4, 2, 1, 32, 3, 3, 1, 8, 38, 23, 3, 2, 2, 7, 43, 4, 6, 2, 1, 10, 47, 14, 2, 4, 4, 53, 5, 12, 58, 35, 59, 3, 61, 62, 1, 64, 5, 6, 40, 3, 2, 2, 12, 12, 8, 74, 10, 76, 2, 2, 6, 4]

cp's OEIS Frontend

A125769 a(n) is the least number j such that j*T_k +/- 1 is n-th prime for some k-th triangular number.

Table of values

List of values

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

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

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