标准2维表问题



设n 是一个正整数。2 × n 的标准2 维表是由正整数1，2，…，2n组成的2 × n数组，该数组的每行从左到右递增，每列从上到下递增。2 × n的标准2 维表全体记为Tab(n)。

给定正整数n，计算Tab(n)中2×n的标准2维表的个数。

-The question of the standard 2-D table for n is a positive integer. 2 × n table of the standard 2-D is a positive integer 1,2, ..., 2n, composed of 2 × n array, the array of each line increasing from left to right, each increasing from top to bottom. 2 × n table of the standard 2-D in mind for all Tab (n). Given positive integer n, the calculation Tab (n) in the standard 2 × n table of the number of 2-D.