a(n) = (b(n) + b(n+1))/3, where b(n) = A000366(n).

A130168

a(n) = (b(n) + b(n+1))/3, where b(n) = A000366(n).

Terms

    a(0) =1a(1) =3a(2) =15a(3) =111a(4) =1131a(5) =15123a(6) =256335a(7) =5364471a(8) =135751731a(9) =4084163643a(10) =144039790455

External references