A383595 - cp's OEIS frontend

A383595 a(n) is the smallest prime k such that (prime(n), k, u, v) are the vertices of a square in Ulam's spiral, where k < u < v are all primes; or -1 if there is no such k.

n	a(n)
1	-1
2	-1
3	-1
4	56527
5	59
6	67
7	251
8	-1
9	-1
10	2473
11	3001
12	43
13	43
14	41
15	173
16	1621
17	61
18	59
19	13
20	141937
21	13
22	13
23	10459
24	331
25	33211
26	643
27	179
28	41
29	41
30	1429
31	11
32	11
33	59
34	59
35	13
36	127
37	163
38	157
39	169957
40	47
41	103
42	56519
43	683
44	2843
45	6841
46	211
47	199
48	311
49	59407
50	439
51	11
52	137
53	274831

[-1, -1, -1, 56527, 59, 67, 251, -1, -1, 2473, 3001, 43, 43, 41, 173, 1621, 61, 59, 13, 141937, 13, 13, 10459, 331, 33211, 643, 179, 41, 41, 1429, 11, 11, 59, 59, 13, 127, 163, 157, 169957, 47, 103, 56519, 683, 2843, 6841, 211, 199, 311, 59407, 439, 11, 137, 274831]

cp's OEIS Frontend

A383595 a(n) is the smallest prime k such that (prime(n), k, u, v) are the vertices of a square in Ulam's spiral, where k < u < v are all primes; or -1 if there is no such k.

Table of values

List of values