first of all, you didn't get the same hole cards, you got 7,4 and 7,3
Given two cards
I think chance that neither card is the same rank would be
44/52 * 43/51 //in both situations we don't want a 7 of aces, hearts, clubs, or spades
The chance that you get one of the cards the same or two cards the same
is
1 - (44/52 *43/51) //the same thing as saying prob of not getting none of the same cards
The chance that you get the same two ranked cards is
8/52*4/51*2 //2 because order doesn't matter, unless you know which card the 7 or other you got first, but give me a break if you did
So the chance that you get exactly one of the cards the same is
1 - (44/52 *43/51) - 8/52*4/51*2
This is roughly 1/4, that you were dealt these cards is pretty unexceptional
In both cases one of those flop cards was also a hole card (this means there are only three 3's or three 4's that can give us what we want, it doesn't matter that's it's three one time, and four the next because multiplication is commutative ...)
So the chances of getting this flop are
(3/50*4/49*4*/48) //if order didn't matter and it was just this set of cards you would multiply by 3choose3
The chances of getting the six are
4/47
The chances of getting an ace on the river are
4/46
We multiply all these odds together to get the odds of this specific board by the river, and we can simplify the expression to
(3*4^4)/(50*49*48*47*46)
This equals roughly 3/1,000,000, so if you square that (because the board ended up this way twice) that's 9/1,000,000,000,000, roughly one in a billion, seems too low a probability
Then again, if someone were to calculate the probability that you'd see something like this before you ever played a single poker game that you'd see something like this, it would be higher.
The difference between this and winning the lottery is that there are only a few lotteries, and it seems like there probably would have been a number of different board hole card combinations that if replicated, would have probably seemed amazing.
Here's a generalization of what you saw: the chance that you get the same different ranks (not the same cards) in the same order on the board is 4^5/(52*51*50*49*48, or 3/1,000,000
If you've seen 100,000 hands let's say, the chance you were gonna see the condition up above at least once is
1 - (1 - 3/1,000,000)^100000
Or 1/4, crazy right
Basically I think how exceptional this is depends on what about it was exceptional for you.