Can someone help me understand why my math doesn't work with this strategy?
Using basic blackjack strategy, bets would follow a grand martingale (1, 3, 7, 15, 31), except that if the bet of 31 is lost, the betting starts over at 1. Now based on googling, there is a 2.8% chance of losing 5 hands in a row or a 2.8% chance of losing the bet of 31. That would mean 97.2% of the time, I would win 1. The expected value of this is about .1 profit per hand and assuming a large enough bankroll, will this not be profitable in the long term? What am I missing? I tested this on a few online sites and have profited quite a bit.