Define u(n) as in A220448; then a(1)=1, thereafter a(n) = u(n)*a(n-1).

A220449

Define u(n) as in A220448; then a(1)=1, thereafter a(n) = u(n)*a(n-1).

Terms

    a(0) =1a(1) =1a(2) =-10a(3) =10a(4) =190a(5) =-730a(6) =-6620a(7) =55900a(8) =365300a(9) =-5864300a(10) =-28269800a(11) =839594600a(12) =2691559000a(13) =-159300557000a(14) =-238131478000

External references