a(n) = sinh((2n-1)*arcsinh(3)).

A173127

a(n) = sinh((2n-1)*arcsinh(3)).

Terms

    a(0) =-3a(1) =3a(2) =117a(3) =4443a(4) =168717a(5) =6406803a(6) =243289797a(7) =9238605483a(8) =350823718557

External references