a(0)=0, a(1)=1, for n>1, a(n) = a(n-1)*2 + floor(a(n-2)/n).

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =8a(5) =16a(6) =33a(7) =68a(8) =140a(9) =287a(10) =588a(11) =1202a(12) =2453a(13) =4998a(14) =10171a(15) =20675a(16) =41985a(17) =85186a(18) =172704a(19) =349891a(20) =708417a(21) =1433495a(22) =2899190a(23) =5860705a(24) =11842209a(25) =23918846a(26) =48293161a(27) =97472205a(28) =196669165a(29) =396699440