另外,n!素数因子的多集的集多部分(集的多集)的个数!。例如,a(2)=1到a(6)=10集合多部分是:
{1} {12} {1}{1}{12} {1}{1}{123} {1}{1}{12}{123}
{1}{2} {1}{1}{1}{2} {1}{12}{13} {1}{12}{12}{13}
{1}{1}{1}{23} {1}{1}{1}{12}{23}
{1}{1}{2}{13} {1}{1}{1}{2}{123}
{1}{1}{3}{12} {1}{1}{2}{12}{13}
{1}{1}{1}{2}{3} {1}{1}{3}{12}{12}
{1}{1}{1}{1}{2}{23}
{1}{1}{1}{2}{2}{13}
{1}{1}{1}{2}{3}{12}
{1}{1}{1}{1}{2}{2}{3}
(结束)