 | ECS #492: 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,Z,Z \right)
\right) \right\}
other formats
3. Coefficients
3.1. First terms
3.2. Recurrence
\displaystyle
\left\{ \left( -4\,n-4 \right) f \left( n \right) +f \left( n+1
\right) =0,f \left( 0 \right) =1 \right\}
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3.3. Closed form
\displaystyle
{4}^{n}n!
other formats
3.4. Asymptotics
4. Exponential generating function
\displaystyle
- \left( -1+4\,x \right) ^{-1}
other formats
5. References
6. Random structure
Search a combinatorial structure by: (firstTerms should be a sequence of integers, separated by commas).