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19h
comment No simple closed form for Bell numbers
The premise of your question is somewhat unclear, because "closed form" is a somewhat variable quantity. Unless you allow factorials in a closed form, I can't think of any basic combinatorial quantity which has one. Allowing them lets in binomial coefficients and therefore Catalan numbers, but what else? Such basic combinatorial quantities as Stirling numbers and the partition function don't have well-known closed forms.
2d
comment Partial sums of Nicomachus's Triangle rows produce Stirling numbers of the 2nd kind?
@FredKline, I'm happy for you to do it, but if you'd rather I do it then I'll take a look. I have an account on OEIS, but I don't yet have much experience in adding stuff to it.
Sep
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reviewed Reject suggested edit on How to find the components of a vector, given magnitude and angle?
Sep
15
reviewed Reviewed Factor and simply using fractions and negative exponents
Sep
15
comment Factor and simply using fractions and negative exponents
Please help us help you by telling us what you're finding difficult.
Sep
15
reviewed Close How do you answer this Bayes theorem question?
Sep
15
reviewed Close What are the root of $x^3 - 2$ $\in \mathbb{R}[x]$?
Sep
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reviewed Close Sumation of the product of two variables
Sep
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reviewed Reopen condition for transitivity
Sep
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revised Partial sums of Nicomachus's Triangle rows produce Stirling numbers of the 2nd kind?
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Sep
12
answered Partial sums of Nicomachus's Triangle rows produce Stirling numbers of the 2nd kind?
Sep
11
revised 4-part partitions of n and 3n
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Sep
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answered Maximum value of $a+b$ given that $\frac{1}{a} + \frac{1}{b} = \frac{1}{20}$
Sep
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reviewed Reject suggested edit on Sign of a series
Sep
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reviewed Close Series expansion of $\log(1+x^2)$
Sep
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answered a 2-regular graph is cyclic or not?
Aug
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reviewed Close Prove a condition for a Banach algebra
Aug
30
answered Pushdown Automata and Challenge in Grammar
Aug
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reviewed Leave Open Generating function for binomial coefficients $\binom{2n+k}{n}$ with fixed $k$
Aug
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reviewed Close In how many ways can a number be expressed as a sum of squares of two natural numbers?