A125869 - cp's OEIS frontend

A125869 Numbers k such that p=10k+1 is prime and cos(2Pi/p) is an algebraic number of a 5-smooth degree, but not 3-smooth.

n	a(n)
1	1
2	3
3	4
4	6
5	10
6	15
7	18
8	24
9	25
10	27
11	40
12	54
13	60
14	64
15	75
16	81
17	120
18	160
19	162
20	180
21	216
22	225
23	300
24	400
25	405
26	480
27	486
28	648
29	768
30	810
31	864
32	900
33	960
34	972
35	1125
36	1440
37	1536
38	1600
39	1944
40	2160
41	2187
42	2250
43	2304
44	2400
45	2560
46	3240
47	3375
48	3645
49	3750
50	4096
51	4320

[1, 3, 4, 6, 10, 15, 18, 24, 25, 27, 40, 54, 60, 64, 75, 81, 120, 160, 162, 180, 216, 225, 300, 400, 405, 480, 486, 648, 768, 810, 864, 900, 960, 972, 1125, 1440, 1536, 1600, 1944, 2160, 2187, 2250, 2304, 2400, 2560, 3240, 3375, 3645, 3750, 4096, 4320]

cp's OEIS Frontend

A125869 Numbers k such that p=10k+1 is prime and cos(2Pi/p) is an algebraic number of a 5-smooth degree, but not 3-smooth.

Table of values

List of values

cp's OEIS Frontend

A125869 Numbers k such that p=10*k+1 is prime and cos(2*Pi/p) is an algebraic number of a 5-smooth degree, but not 3-smooth.

Table of values

List of values

A125869 Numbers k such that p=10k+1 is prime and cos(2Pi/p) is an algebraic number of a 5-smooth degree, but not 3-smooth.