a(n) = A000043(n)-2.

Terms

a(0) =0a(1) =1a(2) =3a(3) =5a(4) =11a(5) =15a(6) =17a(7) =29a(8) =59a(9) =87a(10) =105a(11) =125a(12) =519a(13) =605a(14) =1277a(15) =2201a(16) =2279a(17) =3215a(18) =4251a(19) =4421a(20) =9687a(21) =9939a(22) =11211a(23) =19935a(24) =21699a(25) =23207a(26) =44495a(27) =86241a(28) =110501a(29) =132047