a(n) = A026637(2*n, n-2).

Terms

a(0) =1a(1) =8a(2) =38a(3) =161a(4) =662a(5) =2672a(6) =10676a(7) =42398a(8) =167756a(9) =662252a(10) =2610758a(11) =10283861a(12) =40490702a(13) =159394424a(14) =627456188a(15) =2470223186a(16) =9726696572a(17) =38308366784a(18) =150916209308a(19) =594704861546