A027136 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,2n-k), with T given by A027113.

2, 7, 30, 131, 538, 2153, 8441, 32484, 123292, 462673, 1719899, 6343170, 23237876, 84641287, 306758202, 1106900323, 3978716442, 14252356483, 50897604269, 181263039820, 643928439234, 2282348057593, 8072881497390

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Crossrefs

Cf. A027113.