A163586 - cp's OEIS frontend

A163586 a(1) = 3. For n > 1, Ulam's spiral is started with a(n-1), and the primes p on the NE spoke are considered. a(n) is the minimal p that is the lesser of a twin prime pair.

n	a(n)
1	3
2	5
3	17
4	29
5	41
6	71
7	101
8	191
9	281
10	311
11	617
12	857
13	1319
14	1451
15	1481
16	1721
17	2027
18	2267
19	2729
20	2969
21	2999
22	3461
23	3767
24	4229
25	4241
26	4271
27	20021
28	22091
29	22961
30	23201
31	23291
32	27581
33	31121
34	31151
35	31181
36	32441
37	32531
38	32561
39	32801
40	32831
41	33071
42	33827
43	35897

[3, 5, 17, 29, 41, 71, 101, 191, 281, 311, 617, 857, 1319, 1451, 1481, 1721, 2027, 2267, 2729, 2969, 2999, 3461, 3767, 4229, 4241, 4271, 20021, 22091, 22961, 23201, 23291, 27581, 31121, 31151, 31181, 32441, 32531, 32561, 32801, 32831, 33071, 33827, 35897]

cp's OEIS Frontend

A163586 a(1) = 3. For n > 1, Ulam's spiral is started with a(n-1), and the primes p on the NE spoke are considered. a(n) is the minimal p that is the lesser of a twin prime pair.

Table of values

List of values