a(n) = (sqrt(7)*csc(Pi/7)/2)^n + (-sqrt(7)*csc(2*Pi/7)/2)^n + (-sqrt(7)*csc(4*Pi/7)/2)^n.

A275831

a(n) = (sqrt(7)*csc(Pi/7)/2)^n + (-sqrt(7)*csc(2*Pi/7)/2)^n + (-sqrt(7)*csc(4*Pi/7)/2)^n.

Terms

    a(0) =3a(1) =0a(2) =14a(3) =21a(4) =98a(5) =245a(6) =833a(7) =2401a(8) =7546a(9) =22638a(10) =69629a(11) =211288a(12) =645869a(13) =1966419a(14) =6000099a(15) =18286016a(16) =55765626a(17) =170002805a(18) =518361494a(19) =1580379017a(20) =4818550093a(21) =14691183577a(22) =44792503770a(23) =136568135690a(24) =416385811429

External references