問題詳情
17. For each positive integer N, find three integers a, b, c for which N= Bino(a, 3)+ Bino(b, 2)+ Bino(c, 1), where a＞ b ＞ c ＞=0 and Bino(m, n) =m!/((m-n)!n!). I.e., Bino(m, n) is the well known binomial coefficient and it is 0 when m ＜ n. So N can be represented as abc. For example, let N=3, then a=3, b=2,c=1 and N can be denoted as 321.
【題組】(49) Let N=10, then which is correct about the corresponding abc?
(A)a=4
(B) a+b=6
(C) b+c=2
(D) b=2
(E) atb+c=7.
參考答案
答案：[無官方正解]
難度：計算中-1
書單：沒有書單，新增