I have come across in various books the following formulas :1) N(N-1) for the no DR/BDR scheme, no mentioning about the DR/BDR scheme.2) n(n-1) for the no DR/BDR scheme and (n-2)*2 + 1 = 2n-3 for the DR/BDR scheme3) [n(n-1)]/2 for the no DR/BDR schem...

I think you are right in the first place.I do not see a reason for 2 adjacencies between the DR and BDR.The adjacency relationship is symmetrical.If X is adjacent to Y, then Y is adjacent to X and vise versa.No double-counting should be performed whe...