a(n) = Sum_{k=0..m} (k+1) * A026022(n, m-k), where m=n for n=0,1 and m = floor((n+3)/2) for n >= 2.

Terms

a(0) =1a(1) =3a(2) =8a(3) =20a(4) =32a(5) =79a(6) =128a(7) =312a(8) =512a(9) =1234a(10) =2048a(11) =4888a(12) =8192a(13) =19387a(14) =32768a(15) =76976a(16) =131072a(17) =305902a(18) =524288a(19) =1216536a(20) =2097152a(21) =4840950a(22) =8388608a(23) =19273360a(24) =33554432a(25) =76766564a(26) =134217728a(27) =305877616a(28) =536870912a(29) =1219164499