a(n) = Product_{d|n} binomial(n,d).

Terms

a(0) =1a(1) =2a(2) =3a(3) =24a(4) =5a(5) =1800a(6) =7a(7) =15680a(8) =756a(9) =113400a(10) =11a(11) =79693891200a(12) =13a(13) =4372368a(14) =20495475a(15) =44972928000a(16) =17a(18) =19a(20) =3247700400a(21) =3585005424a(22) =23a(24) =1328250a(25) =87885070000a(26) =370142004375a(28) =29