a(n) = A000252(n) / A065558(n).

Terms

a(0) =1a(1) =3a(2) =12a(3) =16a(4) =80a(5) =36a(6) =252a(7) =128a(8) =324a(9) =240a(10) =1100a(11) =192a(12) =1872a(13) =756a(14) =960a(15) =1024a(16) =4352a(17) =972a(18) =6156a(19) =1280a(20) =3024a(21) =3300a(22) =11132a(23) =1536