A093483(n) + 1.

Terms

a(0) =3a(1) =5a(2) =9a(3) =15a(4) =39a(5) =99a(6) =345a(7) =22269a(8) =79809a(9) =187125a(10) =347979a(11) =2171619a(12) =4219797675a(13) =98059918335