a(n) = T(3n,n), where T is the array defined in A026082.

A026090

a(n) = T(3n,n), where T is the array defined in A026082.

Terms

    a(0) =1a(1) =3a(2) =9a(3) =68a(4) =552a(5) =4524a(6) =37531a(7) =314280a(8) =2651418a(9) =22503384a(10) =191935926a(11) =1643789136a(12) =14126691568a(13) =121764645876

External references