A066771 - cp's OEIS frontend

A066771 a(n) = 5^ncos(2n*arctan(1/2)) or denominator of tan(2narctan(1/2)).

n	a(n)
0	1
1	3
2	-7
3	-117
4	-527
5	-237
6	11753
7	76443
8	164833
9	-922077
10	-9653287
11	-34867797
12	32125393
13	1064447283
14	5583548873
15	6890111163
16	-98248054847
17	-761741108157
18	-2114245277767
19	6358056037323
20	91004468168113
21	387075408075603
22	47340744250793
23	-9392840736385317

[1, 3, -7, -117, -527, -237, 11753, 76443, 164833, -922077, -9653287, -34867797, 32125393, 1064447283, 5583548873, 6890111163, -98248054847, -761741108157, -2114245277767, 6358056037323, 91004468168113, 387075408075603, 47340744250793, -9392840736385317]

cp's OEIS Frontend

A066771 a(n) = 5^ncos(2n*arctan(1/2)) or denominator of tan(2narctan(1/2)).

Table of values

List of values

cp's OEIS Frontend

A066771 a(n) = 5^n*cos(2*n*arctan(1/2)) or denominator of tan(2*n*arctan(1/2)).

Table of values

List of values

A066771 a(n) = 5^ncos(2n*arctan(1/2)) or denominator of tan(2narctan(1/2)).