a(n) = (7*(cot(1*Pi/7))^2)^n + (7*(cot(2*Pi/7))^2)^n + (7*(cot(4*Pi/7))^2)^n.
A287405
a(n) = (7*(cot(1*Pi/7))^2)^n + (7*(cot(2*Pi/7))^2)^n + (7*(cot(4*Pi/7))^2)^n.
Terms
- a(0) =3a(1) =35a(2) =931a(3) =27587a(4) =830403a(5) =25054435a(6) =756187747a(7) =22824258947a(8) =688917131651
External references
- oeis: A287405