a(n) = - sin^2((2n-1)*arccos(sqrt n)) = sin^2((2n-1)*arcsin(sqrt n)) - 1.

A173171

a(n) = - sin^2((2n-1)*arccos(sqrt n)) = sin^2((2n-1)*arcsin(sqrt n)) - 1.

Terms

    a(0) =-1a(1) =0a(2) =49a(3) =23762a(4) =25421763a(5) =48225038404

External references