A027259 a(n) = Sum_{k=0..2n-2} T(n,k) * T(n,k+2), with T given by A025177.

5, 40, 342, 2941, 25333, 218659, 1891683, 16403283, 142548639, 1241293314, 10829045472, 94632148659, 828235716571, 7258991679448, 63701900660206, 559673483274827, 4922447330226279, 43336501329817600, 381873520840930490, 3367815295820010367, 29724409053210972087

Offset: 2

Author

Clark Kimberling

Keywords

• nonn

Extensions

More terms from Sean A. Irvine, Oct 26 2019