Column k=8 of triangle A257673.

Terms

a(0) =1a(1) =24a(2) =300a(3) =2624a(4) =18126a(5) =105552a(6) =539408a(7) =2485016a(8) =10518477a(9) =41482336a(10) =154055260a(11) =543239064a(12) =1830924554a(13) =5929728456a(14) =18534968236a(15) =56121729792a(16) =165117049094a(17) =473276306552