Partial sums of A107947.

Terms

a(0) =1a(1) =3a(2) =6a(3) =11a(4) =17a(5) =25a(6) =36a(7) =52a(8) =69a(9) =88a(10) =110a(11) =137a(12) =170a(13) =211a(14) =263a(15) =331a(16) =400a(17) =471a(18) =545a(19) =624a(20) =709a(21) =802a(22) =906a(23) =1026a(24) =1163a(25) =1319a(26) =1497a(27) =1702a(28) =1940a(29) =2219