a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026769.
A027240
a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026769.
Terms
- a(0) =1a(1) =4a(2) =19a(3) =80a(4) =391a(5) =1738a(6) =8797a(7) =40878a(8) =212491a(9) =1023392a(10) =5426518a(11) =26891674a(12) =144717381a(13) =733600690a(14) =3991767587a(15) =20603079346a(16) =113049604075a(17) =591971513924
External references
- oeis: A027240