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

Terms

a(0) =1a(1) =3a(2) =4a(3) =11a(4) =6a(5) =42a(6) =8a(7) =107a(8) =94a(9) =308a(10) =12a(11) =1718a(12) =14a(13) =3538a(14) =3474a(15) =14827a(16) =18a(17) =68172a(18) =20a(19) =205316a(20) =117632a(21) =705686a(22) =24a(23) =3587174a(24) =53156a(25) =10400952a(26) =4689778a(27) =41321522a(28) =30a(29) =185903342