--snip--
If you have 50k budget to bet there is no way you get 20 red in a rows. i think can make bank with this mehtod if you have good budget.
Sure there is... Let's assume there is no house edge (aka, the most profitable scenario from your point of view). I'm also assuming "original" martingale where you double on losing and reset on winning (your martingale approach will make you lose more money faster during a losing streak, so it'll be even worse)
The odds of rolling 1 time and losing: 1/2, you just lost $20
The odds of rolling 2 times and losing: 1/2 * 1/2 = 1/4, you just lost $20 + $40 = $60
The odds of rolling 3 times and losing: 1/8, you just lost $60 + $80 = $140
The odds of rolling 4 times and losing: 1/16, you just lost $140 + $160 = $300
5 => 1/32, you just lost $300 + $320 = $620
6 => 1/64, you just lost $620 + $640 = $1260
7 => 1/128, you just lost $1260 + $1280 = $2540
8 => 1/256, you just lost $2540 + $2560 = $5100
9 => 1/512, you just lost $5100 + $5120 = $10220
10 => 1/1024, you just lost $10220 + $10240 = $20460
11 => 1/2048, you just lost $20460 + $20480= $40940
And you're done... your $50k bankroll can no longer suffice for continuing...
if you try to win $20 (cause that's all you'll win) for 2048 times, on average you'll lose $40k of your $50k bankroll...