a(n) = 2*A000111(n+1) + A000111(n).

Terms

a(0) =3a(1) =3a(2) =5a(3) =12a(4) =37a(5) =138a(6) =605a(7) =3042a(8) =17257a(9) =108978a(10) =758105a(11) =5759322a(12) =47439277a(13) =421090218a(14) =4006875605a(15) =40686781602a(16) =439122198097