On self-dual double negacirculant codes
  Double negacirculant (DN) codes are the analogues in odd characteristic of double circulant codes. Self-dual DN codes of odd dimension are shown to be consta-dihedral. Exact counting formulae are derived for DN codes. The special class of length a power of two is studied by means of Dickson polynomials, and is shown to contain families of codes with relative distances satisfying a modified Gilbert-Varshamov bound. 
Adel Alahmadi, Hatoon Shohaib, Patrick Sol\'e
cs.IT math.IT