Numbers missing from A109681.

Terms

a(0) =2a(1) =7a(2) =24a(3) =80a(4) =238a(5) =723a(6) =2183a(7) =5653a(8) =19674a(9) =59042a(10) =177145a(11) =531429a(12) =1594313a(13) =4782955a(14) =14348892a(15) =43046708a(16) =129140146a(17) =387420471a(18) =1162261451a(19) =3486784397a(20) =10460353182a(21) =31381059590a(22) =94143178804a(23) =282429536457a(24) =847288609421