a(n) = ceiling(n^2/10).

Terms

a(0) =0a(1) =1a(2) =1a(3) =1a(4) =2a(5) =3a(6) =4a(7) =5a(8) =7a(9) =9a(10) =10a(11) =13a(12) =15a(13) =17a(14) =20a(15) =23a(16) =26a(17) =29a(18) =33a(19) =37a(20) =40a(21) =45a(22) =49a(23) =53a(24) =58a(25) =63a(26) =68a(27) =73a(28) =79a(29) =85