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

1,2

Links

Table of n, a(n) for n=1..26.

Crossrefs

Sequence in context: A379215 A034432 A026962 * A075484 A122739 A038380

Adjacent sequences: A026969 A026970 A026971 * A026973 A026974 A026975

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 20 2019

Status

approved