Product_{n>=1} (1 + x^(2*n))^(a(n)/(2*n)!) = cos(x).

A354173

Product_{n>=1} (1 + x^(2*n))^(a(n)/(2*n)!) = cos(x).

Terms

    a(0) =-1a(1) =-8a(2) =104a(3) =-12032a(4) =354944a(5) =47546368a(6) =6204652544

External references