ECS #544: A simple regular expression in a labelled universe
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ALGO logo ECS #544: A simple regular expression in a labelled universe

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1. Description

No description available

2. Specification

This labelled structure is specified as S in

\displaystyle \left\{ S={\rm Sequence} \left( {\rm Union} \left( Z,Z,{\rm Prod} \left( Z,Z,Z \right) \right) \right) \right\}
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3. Coefficients

3.1. First terms

3.2. Recurrence

\displaystyle \left\{ \left( -{n}^{3}-6\,{n}^{2}-11\,n-6 \right) f \left( n \right) + \left( -2\,n-6 \right) f \left( n+2 \right) +f \left( n+3 \right) =0,f \left( 0 \right) =1,f \left( 1 \right) =2,f \left( 2 \right) =8 \right\}
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3.3. Closed form

\displaystyle \sum _{\alpha={\rm RootOf} \left( -1+2\,{\rm \_Z}+{{\rm \_Z}}^{3} \right) }{\frac {1}{59}}\, \left( 16+12\,{\alpha}^{2}+9\,\alpha \right) {\alpha}^{-n-1}n!
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3.4. Asymptotics

4. Exponential generating function

\displaystyle - \left( -1+2\,x+{x}^{3} \right) ^{-1}
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5. References

EIS A052599

6. Random structure


Search a combinatorial structure by: (firstTerms should be a sequence of integers, separated by commas).

Generated: 2010-02-09 20:53:11 in 2. seconds of elapsed time.
Based on commit 9d1e479..., Fri Jul 10 14:52:30 2009 +0200.
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