A306196 - cp's OEIS frontend

A306196 Irregular triangle read by rows where row n lists the primes 2n - k, with 1 < k < 2n-1, and if k is composite also 2n - p has to be prime for some prime divisor p of k.

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

[2, 3, 2, 3, 5, 3, 5, 7, 2, 5, 7, 2, 3, 5, 7, 11, 3, 5, 7, 11, 13, 3, 5, 7, 11, 13, 2, 3, 5, 7, 11, 13, 17, 2, 3, 5, 7, 11, 13, 17, 19, 2, 3, 5, 7, 11, 13, 17, 19, 2, 3, 5, 7, 11, 13, 17, 19, 23, 3, 5, 11, 13, 17, 23, 2, 7, 11, 13, 17, 19, 23, 2, 3, 5, 11, 13, 17, 19, 23, 29]

cp's OEIS Frontend

A306196 Irregular triangle read by rows where row n lists the primes 2n - k, with 1 < k < 2n-1, and if k is composite also 2n - p has to be prime for some prime divisor p of k.

Table of values

List of values

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

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

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