16779264domain: NAppears in sequencesa(n) = (2^n + 2^[ n/2 ] )/2.at n=23A001445Number of 4-ary Lyndon words of length n over GF(4) with trace 0 and subtrace 0.at n=15A074446a(n) = 2^(2n) + 2^(n-1).at n=11A164051