A258780 - cp's OEIS frontend

A258780 a(n) is the least k such that k^2 + 1 is a semiprime p*q, p < q, and (q - p)/2^n is prime.

n	a(n)
2	8
3	12
4	140
5	64
6	2236
7	196
8	1300
9	1600
10	6256
11	5084
12	248756
13	246196
14	484400
15	36680
16	887884
17	821836
18	1559116
19	104120
20	126072244
21	9586736
22	4156840
23	542759984
24	1017981724
25	2744780140
26	405793096
27	148647496
28	1671024916

[8, 12, 140, 64, 2236, 196, 1300, 1600, 6256, 5084, 248756, 246196, 484400, 36680, 887884, 821836, 1559116, 104120, 126072244, 9586736, 4156840, 542759984, 1017981724, 2744780140, 405793096, 148647496, 1671024916]

cp's OEIS Frontend

A258780 a(n) is the least k such that k^2 + 1 is a semiprime p*q, p < q, and (q - p)/2^n is prime.

Table of values

List of values