Dynkin type C5—grassmannian.info
Dynkin type $\mathrm{ C }_{ 5 }$
«$\mathrm{ C }_{ 4 }$
$\mathrm{ C }_{ 6 }$»
$2n=10$
$2n^2+n=55$
$1,3,5,\ldots,2n-1=1,3,5,7,9$
$\mathrm{S}_{ 5 }\rtimes(\mathbb{Z}/2\mathbb{Z})^{\oplus 5 }$
$n!2^n=5!2^{ 5 }=3840$
$2n^2=50$
\begin{pmatrix} 2 & -1 & 0 & 0 & 0 \\ -1 & 2 & -1 & 0 & 0 \\ 0 & -1 & 2 & -1 & 0 \\ 0 & 0 & -1 & 2 & -1 \\ 0 & 0 & 0 & -2 & 2 \\ \end{pmatrix}