Partial sums of A007584.

Terms

a(0) =1a(1) =11a(2) =45a(3) =125a(4) =280a(5) =546a(6) =966a(7) =1590a(8) =2475a(9) =3685a(10) =5291a(11) =7371a(12) =10010a(13) =13300a(14) =17340a(15) =22236a(16) =28101a(17) =35055a(18) =43225a(19) =52745a(20) =63756a(21) =76406a(22) =90850a(23) =107250a(24) =125775a(25) =146601a(26) =169911a(27) =195895a(28) =224750a(29) =256680