a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026681.
A026989
a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026681.
Terms
- a(0) =1a(1) =14a(2) =115a(3) =660a(4) =3805a(5) =20520a(6) =109779a(7) =551774a(8) =2921313a(9) =14482320a(10) =71576096a(11) =349292330a(12) =1804636693a(13) =8745745676a(14) =42107640345a(15) =203559063050
External references
- oeis: A026989