Column 1 of A122832.

Terms

a(0) =0a(1) =1a(2) =2a(3) =9a(4) =28a(5) =125a(6) =486a(7) =2317a(8) =10424a(9) =53433a(10) =267850a(11) =1470161a(12) =8032212a(13) =46925749a(14) =275437358a(15) =1702883925a(16) =10630404976a(17) =69192858737a(18) =455957606034