Here is a rundown of the numbers that are already taken.
00 (Bob's BBQ Buffet)
7 (Project Kahn)
11 (TheRealFoXQc)
12 (Live2surfmtk)
13 (Conkinator451)
14 (cagedranger45)
15 (JU240)
16 (Capitol614)
17 (NightFox17)
20 (Bullish)
23 (Stone Adams)
26 (atomik47)
27 (DelayedPenalty)
33 (CivicSista)
42 (killall42)
47 (Chuckytt)
56 (ShentR)
58 (StillwaterOK)
66 (Redman Racer)
67 (lxegtr)
72 (dividedwefallo21)
82 (UP1DOWN5)
83 (Aceshigh)
84 (SuperTone1984)
85 (SAMHAIN9385)
86 (Lone Wolf886)
88 (chmashdejare)
89 (JR89)
90 (popojep)
95 (CREEPINDONKEY)
97 (Brad02gt)
98 (krauos)
99 (KillingPointman)
129 (Flier129)
Don't see the number you want? You're in luck! That number is still available.
So there's no confusion, if a number is reserved in one series, it is considered reserved in the other, even if the driver doesn't intend to run both.