a(n) = T(2*n+4,n), array T as in A055807.

Terms

a(0) =1a(1) =31a(2) =192a(3) =1120a(4) =6400a(5) =36288a(6) =205184a(7) =1159488a(8) =6554880a(9) =37088480a(10) =210075712a(11) =1191254688a(12) =6762782208a(13) =38434677120a(14) =218663320320