Number of 4-unbalanced strings of length n (=2^n-A027559(n)).

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =2a(6) =6a(7) =22a(8) =56a(9) =152a(10) =356a(11) =858a(12) =1914a(13) =4334a(14) =9372a(15) =20440a(16) =43280a(17) =92114a(18) =192182a(19) =402246a(20) =830328a(21) =1717496a(22) =3517668a(23) =7214218a(24) =14689994a(25) =29938526a(26) =60697148a(27) =123127224a(28) =248807472a(29) =502963778