a(n) = 6*a(n-1) + 3*(2^(n-2)-1) for n > 2, a(0)=a(1)=a(2)=0.

A241271

a(n) = 6*a(n-1) + 3*(2^(n-2)-1) for n > 2, a(0)=a(1)=a(2)=0.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =3a(4) =27a(5) =183a(6) =1143a(7) =6951a(8) =41895a(9) =251751a(10) =1511271a(11) =9069159a(12) =54418023a(13) =326514279a(14) =1959097959a(15) =11754612327a(16) =70527723111a(17) =423166436967

External references