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4 votes
2 answers
275 views

An inequality involving binomial coefficients and the powers of two

I came across the following inequality, which should hold for any integer $k\geq 1$: $$\sum_{j=0}^{k-1}\frac{(-1)^{j}2^{k-1-j}\binom{k}{j}(k-j)}{2k+1-j}\leq \frac{1}{3}.$$ I have been struggling with ...
macat's user avatar
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0 answers
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Estimating when does a certain binomial sum exceed an upper bound

Given a fixed integer $n > 0$ and $0 \le m \le n$ let us define the numbers $$f_{n,m} = \sum_{i=\lfloor m/2 \rfloor}^m {n-2i \choose n - m -i}{i+1 \choose m - i +1}.$$ For example $f_{n,0} = 1,f_{...
Jernej's user avatar
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