Nope, you’re totally right, my mistake. I used the opposite probability aka (5/X) + (1-(5/X)).(5/(X-1)) = 0.5 which conducts (now) to the same polynome as yours.
Man, I got rusty.
I counted 21 cards if you need 6 combo starters btw (verified) and 14.17 for 4 combo starters (verified too).
I think ppl should learn those results by heart instead of counting ingame, which is next to impossible.
So 15, 18 and 21 are the numbers to remember for 4, 5 and 6 combo starters and 50% chance to still fire through Utopia.
That’s also mean that if the corp have less than 15 cards, then try playing Utopia before PS is a good move.
OT’s:
This is just solving this.
Hades is easier to solve (before PS, Runner’s score+R&D+Archives must be < 7 points, so please fload agendas to HQ to actually win) - which also means Utopia is, again, a key in this matchup.
(That would conclude what I was saying to a “almost as much stubborn @Calimsha as me”, on R4G : Utopia, best WyldMaxx card ever, for times, and times to come.).