a(n) = A104350(n) + 1.

Terms

a(0) =2a(1) =3a(2) =7a(3) =13a(4) =61a(5) =181a(6) =1261a(7) =2521a(8) =7561a(9) =37801a(10) =415801a(11) =1247401a(12) =16216201a(13) =113513401a(14) =567567001a(15) =1135134001a(16) =19297278001a(17) =57891834001