The number of 1-length gaps in all possible covers of n-length line by 2-length segments.

Terms

a(0) =0a(1) =1a(2) =0a(3) =2a(4) =2a(5) =3a(6) =6a(7) =7a(8) =12a(9) =17a(10) =24a(11) =36a(12) =50a(13) =72a(14) =102a(15) =143a(16) =202a(17) =282a(18) =394a(19) =549a(20) =762a(21) =1057a(22) =1462a(23) =2019a(24) =2784a(25) =3832a(26) =5268a(27) =7232a(28) =9916a(29) =13581