Number of binary sequences of length n having a conjugate at Hamming distance 2.

Terms

a(0) =0a(1) =2a(2) =6a(3) =12a(4) =30a(5) =54a(6) =98a(7) =160a(8) =234a(9) =400a(10) =462a(11) =864a(12) =806a(13) =1722a(14) =1530a(15) =3328a(16) =1938a(17) =7290a(18) =2774a(19) =13360a(20) =6090a(21) =26422a(22) =5106a(23) =60096a(24) =7900a(25) =113256a(26) =21600a(27) =240240a(28) =10614a(29) =535980