Column 1 of triangle A106340.A106341Column 1 of triangle A106340.Terms a(0) =1a(1) =-3a(2) =9a(3) =-45a(4) =585a(5) =-21105a(6) =1858185a(7) =-367958745a(8) =157169540745External referencesoeis: A106341