E.g.f.: Sum_{n>=0} Product_{k=1..n} tan((2*k-1)*x).

A221080

E.g.f.: Sum_{n>=0} Product_{k=1..n} tan((2*k-1)*x).

Terms

    a(0) =1a(1) =1a(2) =6a(3) =92a(4) =2760a(5) =134416a(6) =9626976a(7) =952336832a(8) =124374587520

External references