a(n) = (1/2)*A014431(n+2).

Terms

a(0) =1a(1) =1a(2) =3a(3) =7a(4) =21a(5) =61a(6) =191a(7) =603a(8) =1961a(9) =6457a(10) =21595a(11) =72975a(12) =249085a(13) =857013a(14) =2970007a(15) =10356323a(16) =36311633a(17) =127937649a(18) =452738867a(19) =1608426647a(20) =5734534629a(21) =20511509549a(22) =73583105007a(23) =264687136235a(24) =954482676217