A026972 a(n) = Sum_{k=0..n-1} T(n,k) * T(n,k+1), with T given by A026648.

1, 6, 24, 108, 406, 1908, 7289, 34248, 131766, 623700, 2416836, 11487528, 44745468, 213451560, 834897375, 3993910416, 15673923910, 75152083716, 295737641768, 1420670333640, 5603322265428, 26960309526744, 106539505068194, 513309625743600, 2031786103702780, 9800639852315208

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Extensions

More terms from Sean A. Irvine, Oct 20 2019