 | ECS #393 |
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1. Description
No description available
2. Specification
This unlabelled structure is specified as S in
\displaystyle
\left\{ S={\rm Sequence} \left( {\rm Prod} \left( Z,{\rm Union}
\left( Z,{\rm Prod} \left( Z,Z \right) \right) \right) \right)
\right\}
other formats
3. Coefficients
3.1. First terms
3.2. Recurrence
\displaystyle
\left\{ f \left( n \right) +f \left( n+1 \right) -f \left( n+3
\right) =0,f \left( 0 \right) =1,f \left( 1 \right) =0,f \left( 2
\right) =1 \right\}
other formats
3.3. Closed form
\displaystyle
\sum _{\alpha={\rm RootOf} \left( -1+{{\rm \_Z}}^{2}+{{\rm \_Z}}^{3}
\right) }-1/23\, \left( -3-7\,\alpha+2\,{\alpha}^{2} \right) {\alpha}^
{-1-n}
other formats
3.4. Asymptotics
4. Ordinary generating function
\displaystyle
- \left( -1+{x}^{2}+{x}^{3} \right) ^{-1}
other formats
5. References
6. Random structure
Search a combinatorial structure by: (firstTerms should be a sequence of integers, separated by commas).