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problem solving/Project Euler

Problem 53 - How many values of C(n,r), for 1 ≤ n ≤ 100, exceed one-million?

링크

There are exactly ten ways of selecting three from five, 12345:

123, 124, 125, 134, 135, 145, 234, 235, 245, and 345

In combinatorics, we use the notation, ^(5)C_(3) = 10.

In general,

^(n)C_(r) =
n!
r!(n−r)!
,where r ≤ n, n! = n×(n−1)×...×3×2×1, and 0! = 1.

It is not until n = 23, that a value exceeds one-million: ^(23)C_(10) = 1144066.

How many, not necessarily distinct, values of  ^(n)C_(r), for 1 ≤ n ≤ 100, are greater than one-million?


python