tan(arctanh(x)*tanh(x))=2/2!*x^2+400/6!*x^6+2688/8!*x^8...

A012755

tan(arctanh(x)*tanh(x))=2/2!*x^2+400/6!*x^6+2688/8!*x^8...

Terms

    a(0) =0a(1) =2a(2) =0a(3) =400a(4) =2688a(5) =1631488a(6) =60938240a(7) =35243972608

External references