Continued cotangent recurrence a(n+1)=a(n)^3+3*a(n) and a(1)=15.

A145189

Continued cotangent recurrence a(n+1)=a(n)^3+3*a(n) and a(1)=15.

Terms

    a(0) =15a(1) =3420a(2) =40001698260

External references