Number of ternary words of length n (beginning 0) with autocorrelation function 2^(n-1)+2.

Terms

a(0) =0a(1) =0a(2) =0a(3) =2a(4) =6a(5) =16a(6) =54a(7) =154a(8) =480a(9) =1418a(10) =4302a(11) =12836a(12) =38670a(13) =115802a(14) =347868a(15) =1042970a(16) =3130350a(17) =9389152a(18) =28171710a(19) =84509410a(20) =253541136a(21) =760606270a(22) =2281857318a(23) =6845520448a(24) =20536677354a(25) =61609877590a(26) =184829980176a(27) =554489476858