I found the wikipedia article mostly incomprehensible but it says a few things. You are probably better off asking on MSE or Reddit, sorry to say. Wikipedia’s math reference desk has slowed down a lot in recent years though that’s possibly another place to try.
Does that mean they are enlarging the inventory now? As opposed to dismantling old bombs as they make new ones (modernization while keeping the number constant)? I thought there was a treaty capping the total number but haven’t been keeping track.