A154722 - cp's OEIS frontend

A154722 Triangle read by rows in which row n lists: n, in the center of the row and the pairs of noncomposite numbers that are equidistant to n, as shown below in the example.

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

[1, 1, 2, 3, 1, 3, 5, 1, 3, 4, 5, 7, 3, 5, 7, 1, 5, 6, 7, 11, 1, 3, 7, 11, 13, 3, 5, 8, 11, 13, 1, 5, 7, 9, 11, 13, 17, 1, 3, 7, 10, 13, 17, 19, 3, 5, 11, 17, 19, 1, 5, 7, 11, 12, 13, 17, 19, 23, 3, 7, 13, 19, 23, 5, 11, 14, 17, 23, 1, 7, 11, 13, 15]

cp's OEIS Frontend

A154722 Triangle read by rows in which row n lists: n, in the center of the row and the pairs of noncomposite numbers that are equidistant to n, as shown below in the example.

Table of values

List of values

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

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

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