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Ben Brink
Posts:
201
From:
Rosenberg, TX
Registered:
11/11/06


Edu59 Post
Posted:
Oct 1, 2011 2:41 PM



Folks, Again assumng I understand the problem: Since the combinations are size 5, we're looking for the sum from i = 1 to i = 16 of C(20i2,3). Hopefully this counts the combinations with 1, 4 and three other elements larger than 1 but not 4; 2, 5 and three other elements larger than 2 but not 5; etc. There can only be 16 summands since there are not three integers in K greater than 17 but not 20. Again, I know some of you guys have combinatorial cannons compared to my peashooter! Please take something out of the drawer and help Edu59. Thanks. Ben



