a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026648.
A026972
a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026648.
Terms
- a(0) =1a(1) =6a(2) =24a(3) =108a(4) =406a(5) =1908a(6) =7289a(7) =34248a(8) =131766a(9) =623700a(10) =2416836a(11) =11487528a(12) =44745468a(13) =213451560a(14) =834897375a(15) =3993910416a(16) =15673923910a(17) =75152083716a(18) =295737641768
External references
- oeis: A026972