A075340 - cp's OEIS frontend

A075340 a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).

n	a(n)
1	1
2	2
3	9
4	19
5	20
6	41
7	42
8	43
9	44
10	89
11	90
12	181
13	182
14	547
15	548
16	1097
17	1098
18	7687
19	7688
20	15377
21	15378
22	30757
23	30758
24	276823
25	276824
26	553649
27	553650
28	2768251
29	2768252
30	8304757
31	8304758
32	99657097
33	99657098
34	199314197
35	199314198
36	3189027169

[1, 2, 9, 19, 20, 41, 42, 43, 44, 89, 90, 181, 182, 547, 548, 1097, 1098, 7687, 7688, 15377, 15378, 30757, 30758, 276823, 276824, 553649, 553650, 2768251, 2768252, 8304757, 8304758, 99657097, 99657098, 199314197, 199314198, 3189027169]

cp's OEIS Frontend

A075340 a(1) = 1; a(2n) is the smallest prime == 1 mod (a(2n-1)) and a(2n+1) is the smallest composite number == 1 (mod a(2n)).

Table of values

List of values