a(n) = floor(Sum_{k=1..n} sqrt(k)).

Terms

a(0) =0a(1) =1a(2) =2a(3) =4a(4) =6a(5) =8a(6) =10a(7) =13a(8) =16a(9) =19a(10) =22a(11) =25a(12) =29a(13) =32a(14) =36a(15) =40a(16) =44a(17) =48a(18) =52a(19) =57a(20) =61a(21) =66a(22) =70a(23) =75a(24) =80a(25) =85a(26) =90a(27) =95a(28) =101a(29) =106