a(n) = Sum_{k=0..floor(n/2)+1} (k+1) * A026009(n, k).

Terms

a(0) =1a(1) =3a(2) =8a(3) =16a(4) =39a(5) =77a(6) =179a(7) =354a(8) =799a(9) =1584a(10) =3504a(11) =6960a(12) =15174a(13) =30183a(14) =65085a(15) =129598a(16) =277071a(17) =552140a(18) =1172348a(19) =2337624a(20) =4935586a(21) =9845978a(22) =20691318a(23) =41292196a(24) =86432614a(25) =172538352a(26) =359934704a(27) =718680768a(28) =1494861996a(29) =2985378027