Swedish Lotto rules can be found here. As far as I know these are the most recent rules. In several places the probability of winning Drömvinsten is quoted as 1:337,915,578. However, if I try to recalculate this number, I get 336,227,681 = 6724520 * 50.00025. I seem to match the odds for Joker and for the Swedish Lotto. But my 'product' is obviously off by some 1,7 million.
I understand for Joker the player needs to match either two leading or ending digits to be eligible for any payout.
Any ideas what I am missing?
Note: I don't speak Swedish, so I machine translated the rules.
EDIT: I meanwhile found a formula leading to the 1 in 337,915,578. See grey cells in my table. However I yet need to find out why the 17991 combinations are not 18000 (i.e. 9 combinations are seemingly not eligible to win that class).
My calculations are
Your attempted calculations seem to ignore the possibility of the ending digits outperforming the leading digits as well as your attempted calculations seem to ignore the possibility of the ending digits performing just as well as the leading digits. For exactly two leading or ending to match, we need one of the following scenarios for (start,end): (2,0),(2,1),(2,2),(0,2),(1,2) which would give $0.9^2(2\cdot.1^2+2\cdot .1^3+.1^4)=0.017901$
Similarly for three leading or ending to match we have $0.9^2(2\cdot .1^3+2\cdot .1^4+2\cdot .1^5 + .1^6) = 0.00179901$ or zero leading or ending to match would just be $0.9^2 = 0.81$
The reason why the other numbers in your grey table match is because in order for 4 or more numbers to match in the leading numbers it is impossible for the opposite direction to match or exceed the performance without causing all numbers to match.