A216565 - cp's OEIS frontend

A216565 Numbers n such that the n-th Lucas number is prime, but cannot be written in the form a^2 + 5*b^2.

n	a(n)
1	0
2	2
3	5
4	7
5	8
6	11
7	16
8	17
9	19
10	37
11	41
12	47
13	53
14	71
15	79
16	113
17	353
18	503
19	617
20	863
21	1097
22	1361
23	4787
24	4793
25	8467
26	10691
27	12251
28	14449
29	19469
30	35449
31	36779
32	44507
33	51169
34	56003
35	81671
36	89849
37	94823
38	140057
39	148091
40	159521
41	183089
42	202667
43	443609
44	532277
45	574219
46	616787
47	631181
48	637751
49	651821
50	692147

[0, 2, 5, 7, 8, 11, 16, 17, 19, 37, 41, 47, 53, 71, 79, 113, 353, 503, 617, 863, 1097, 1361, 4787, 4793, 8467, 10691, 12251, 14449, 19469, 35449, 36779, 44507, 51169, 56003, 81671, 89849, 94823, 140057, 148091, 159521, 183089, 202667, 443609, 532277, 574219, 616787, 631181, 637751, 651821, 692147]

cp's OEIS Frontend

A216565 Numbers n such that the n-th Lucas number is prime, but cannot be written in the form a^2 + 5*b^2.

Table of values

List of values