a(n) = Sum_{d|n} d^(n/d) * binomial(n/d,d).

Terms

a(0) =1a(1) =2a(2) =3a(3) =8a(4) =5a(5) =30a(6) =7a(7) =104a(8) =36a(9) =330a(10) =11a(11) =1296a(12) =13a(13) =2702a(14) =2445a(15) =7440a(16) =17a(17) =33030a(18) =19a(19) =51220a(20) =76566a(21) =112662a(22) =23a(23) =699216a(24) =3150a(25) =639002a(26) =1653399a(27) =2064412a(28) =29a(29) =10620300