Denominator of Sum_{i+j+k=n; i,j,k > 0} 1/(i*j*k).

Terms

a(0) =1a(1) =2a(2) =4a(3) =8a(4) =15a(5) =240a(6) =15120a(7) =672a(8) =8400a(9) =100800a(10) =69300a(11) =4950a(12) =17199000a(13) =22422400a(14) =33633600a(15) =201801600a(16) =467812800a(17) =102918816000a(18) =410646075840a(19) =3555377280a(20) =215100325440a(23) =190281057120