Question 1027928
{{{N(q)=(1/6)q^3+(1/2)q^2+(1/3)q}}}
{{{N(q)=(1/6)q^3+(3/6)q^2+(2/6)q}}}
{{{N(q)=(1/6)(q^3+3q^2+2q)}}}
{{{highlight(N(q)=(q(q+1)(q+2))/6)}}}