Four-quotient of the partition three-one (source code)

= Four-quotient of the partition three-one
{title2=$Q_4(3,1)$}

With runners ordered by residues $0,1,2,3$, an abacus for $(3,1)$ gives
$$
Q_4(3,1)=(\varnothing,\varnothing,(1),\varnothing).
$$