Is it (2n)!n!^{2}
Consider a n*n chessboard. A person moves along the lines of the chessboard such that the sum in the y axis is greater than or equal to the sum in the x axis. Find the number of ways of going from one corner to the other corner.

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7 Answers
Sigma
·20120427 01:33:00
@Shaswata: ur ans wud hav been correct if the q wud hav been: In how many shortest possible ways can 1 reach the diagonal opp sides of the chessboard??
Shubhodip
·20120517 04:17:32
This is Catalan numbers.
The answer is C_{n1}
Just look at the permutation matrix and you are done. (Basically a bijection)
I don't have time to explain sorry
sougata nag
·20120603 00:59:57
let the no be g.
then 2g=Î£_{1â†’n}2r_{Cr}+Î£_{1â‰¤i,jâ‰¤n}i+j_{Ci}
 Shubhodip what Upvote·0· Reply ·20120606 09:41:33