[Math] How many combinations for 3 cards from a deck of 52 cards if they have to be in ascending order

combinationscombinatorics

If I wanted the different 3-card possible combinations from a total of 4 cards in ascending order, I would have:

$(1,2,3)$

$(1,2,4)$

$(1,3,4)$

$(2,3,4)$

EIDT:

How can I get all the possible, unique triplets in ascending order given an arbitrarily selected subset of cards from a standard deck of 52 cards?

I was misunderstanding the problem. Here's a bigger example, I'm given the cards:

$6, 1, 4, 3, 2, 4, 5$

  • I can have more than one card with the same number, but each triplet cannot contain repeated numbers.
  • Each triplet has to be in ascending order, but within the constraints of the original order.

In this example, the number 6 cannot appear in any triplet.
The first 4 isn't going to appear in any triplet either, but the second 4 allows to form (1,4,5). The results are:

$(1,4,5)$

$(1,2,4)$

$(1,2,5)$

$(3,4,5)$

$(2,4,5)$

With these restrictions in place, it's probably not a combinatorics problem.

Best Answer

Hint: for any triplet there are $6$ orders and you accept $1$. Do you want the number of them or a list. The list will be too large for most purposes.

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