The name of this system, the 1-3-2-6 betting system, really explains it all. It's a system based on the betting pattern 1 unit, then 3 units, then 2 units, then 6 units. This type of blackjack betting system is based on the Paroli system and it's based on the premise that you can win 4 times in a row.
This system is a positive progression betting system which means you increase the betting amount when you win.
By using the 1-3-2-6 betting strategy, the first bet is 1 unit, the second bet is 3 units, the third bet is 2 units, and the fourth bet is 6 units. For this example we will assume each unit is $5 and you have even money odds of 1:1.
Your first bet would be $5. After winning this bet, $5 is added to the $10 on the table which makes the second bet $15. After winning this bet there will be a total of $30 on the table. You take back $20 and the third bet is now $10. If your third bet is also a winner, you will have $20 left on the table. Add $10, making a total of $30 for the fourth bet.
Finally, if the fourth bet wins, there will be a total of $60 left on the table, which is all your net profit. Now you've completed the betting cycle so you loop back and start all over again. If you lose a bet at any point before the betting cycle is completed, you start back over with the original $5 bet.
The 1-3-2-6 blackjack betting system is an interesting strategy. With this system you are risking a small amount to win a much larger amount, if you complete the betting cycle. You can lose 6 times at the worst level, the second bet, and still completely cover yourself by winning all 4 bets of the cycle one time
It is generally not recommended that you use the 1-3-2-6 betting system for blackjack unless you are just playing for fun. You are required to win 4 hands in a row to completely cycle the system and turn your profit. This system would be fun for a recreational player but no serious blackjack player should use this betting strategy to try to turn large profits.