Partial sums of A050404.

Terms

a(0) =1a(1) =15a(2) =92a(3) =372a(4) =1170a(5) =3102a(6) =7260a(7) =15444a(8) =30459a(9) =56485a(10) =99528a(11) =167960a(12) =273156a(13) =430236a(14) =658920a(15) =984504a(16) =1438965a(17) =2062203a(18) =2903428a(19) =4022700a(20) =5492630a(21) =7400250a(22) =9849060a(23) =12961260a(24) =16880175a(25) =21772881a(26) =27833040a(27) =35283952a(28) =44381832a(29) =55419320