A026989 a(n) = Sum_{k=0..n-3} T(n,k) * T(n,k+3), with T given by A026681.

1, 14, 115, 660, 3805, 20520, 109779, 551774, 2921313, 14482320, 71576096, 349292330, 1804636693, 8745745676, 42107640345, 203559063050, 1040682784201, 5002217935308, 23823427871991, 114772726273528, 583453635620973, 2795288971320092, 13246283464422706, 63736681240596050

Offset

3,2

Links

Table of n, a(n) for n=3..26.

Crossrefs

Sequence in context: A027204 A200037 A026959 * A204240 A178258 A121783

Adjacent sequences: A026986 A026987 A026988 * A026990 A026991 A026992

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Oct 21 2019

Status

approved