a(n) = Sum_{k=0..floor(n/3)} |Stirling1(n - 2*k,k)|.

Terms

a(0) =1a(1) =0a(2) =0a(3) =1a(4) =1a(5) =2a(6) =7a(7) =27a(8) =131a(9) =771a(10) =5320a(11) =42119a(12) =376174a(13) =3740018a(14) =40956593a(15) =489749100a(16) =6348744124a(17) =88677555115