Exactly what OP says, but has to be minimum of 3 games in a franchise to count (So no splatoon for exanple)

Goooooooo answer!

Is Uncharted 3 sales greater than 2? If so thats one woth 4 installments

Super Smash Bros counts
SSB 5.5mil
SSBM 7mil
SSBB 13mil
SSB4 14mil and counting

The Witcher?!? I think that one has grown with each installment.

Nintendo considers 3DS to be the 4th game, and Wii U to be the 5th game.

Sakurai: No, actually, there was never any consideration to having him in previous games, and if you think about it, there hasn't been really a precedent for third-party characters joining other than very special cases like Sonic, during the last game. It's something that wasn't even possible. We're now going into versions four and five within the series—this is only something that's now possible.

Kotaku: When you say four and five, do you mean the 3DS and Wii U versions? Those are separate?

Sakurai: Yeah, exactly.

It is the same game but its not. A weirs case.... Ok if its not counted then what other games are?

Monster Hunter counting the first installment in each generation;

Monster Hunter: 0.5 mil

Monster Hunter 2: 0.63 mil

Monster Hunter Tri: 2.22 mil

Monster Hunter 4: 3.44 mil

Counting the enhanced versions breaks it at Monster Hunter 2 though;

Monster Hunter + G versions: 0.98 mil

Monster Hunter 2: 0.63 mil

Monster Hunter Tri + Ultimate versions: 5.7 mil

Monster Hunter 4 + Ultimate version: 7.39 mil

Uncharted and The Witcher for sure

Maybe Bioshock as well? not sure about this one.

COD and GTA are prettt obvious ones.

I think The Elder Scrolls? We don't have numbers for the first two games though.

Is Fallout: New Vegas a spinoff or mailine game?