 | ECS #441 |
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1. Description
No description available
2. Specification
This unlabelled structure is specified as S in
\displaystyle
\left\{ S={\rm Union} \left( Z,{\rm Prod} \left( Z,{\rm Union} \left(
Z,{\rm Prod} \left( S,S \right) \right) \right) \right) \right\}
other formats
3. Coefficients
3.1. First terms
3.2. Recurrence
\displaystyle
\left\{ \left( -2+4\,n \right) f \left( n \right) + \left( 4\,n+4
\right) f \left( 1+n \right) + \left( -4-n \right) f \left( n+3
\right) =0,f \left( 0 \right) =0,f \left( 1 \right) =1,f \left( 2
\right) =1 \right\}
other formats
3.3. Asymptotics
4. Ordinary generating function
\displaystyle
-1/2\,{\frac {-1+\sqrt {1-4\,{x}^{2}-4\,{x}^{3}}}{x}}
other formats
5. References
6. Random structure
Search a combinatorial structure by: (firstTerms should be a sequence of integers, separated by commas).