Number of combinations of n things from 1 to n at a time, with repeats allowed.

A030662

Number of combinations of n things from 1 to n at a time, with repeats allowed.

Terms

    a(0) =1a(1) =5a(2) =19a(3) =69a(4) =251a(5) =923a(6) =3431a(7) =12869a(8) =48619a(9) =184755a(10) =705431a(11) =2704155a(12) =10400599a(13) =40116599a(14) =155117519a(15) =601080389a(16) =2333606219a(17) =9075135299a(18) =35345263799a(19) =137846528819a(20) =538257874439

External references