First bisection of A164869.

Terms

a(0) =0a(1) =12a(2) =120a(3) =252a(4) =240a(5) =660a(6) =32760a(7) =84a(8) =8160a(9) =14364a(10) =6600a(11) =3036a(12) =65520a(13) =156a(14) =24360a(15) =429660a(16) =16320a(17) =204a(18) =69090840a(19) =228a(20) =541200a(21) =75852a(22) =30360a(23) =12972a(24) =2227680a(25) =3300a(26) =82680a(27) =43092a(28) =48720a(29) =20532