A258840 - cp's OEIS frontend

A258840 a(n) is the least integer k such that there are n values of i <= k for which gpf(i^2 + 1) = gpf(k^2 + 1), where gpf(x) is the greatest prime factor of x.

n	a(n)
1	1
2	3
3	7
4	38
5	47
6	157
7	302
8	327
9	515
10	616
11	697
12	798
13	818
14	1303
15	2818
16	3141
17	3323
18	5648
19	6962
20	9193
21	9872
22	13213
23	13747
24	15445
25	16271
26	17149
27	18263
28	20491
29	20727
30	24389
31	26915
32	29078
33	31867
34	37848
35	38007
36	40182
37	41508
38	43328
39	46349
40	55025
41	62258
42	63133
43	66893

[1, 3, 7, 38, 47, 157, 302, 327, 515, 616, 697, 798, 818, 1303, 2818, 3141, 3323, 5648, 6962, 9193, 9872, 13213, 13747, 15445, 16271, 17149, 18263, 20491, 20727, 24389, 26915, 29078, 31867, 37848, 38007, 40182, 41508, 43328, 46349, 55025, 62258, 63133, 66893]

cp's OEIS Frontend

A258840 a(n) is the least integer k such that there are n values of i <= k for which gpf(i^2 + 1) = gpf(k^2 + 1), where gpf(x) is the greatest prime factor of x.

Table of values

List of values