a(n) = ceiling(n^2/8).

Terms

a(0) =0a(1) =1a(2) =1a(3) =2a(4) =2a(5) =4a(6) =5a(7) =7a(8) =8a(9) =11a(10) =13a(11) =16a(12) =18a(13) =22a(14) =25a(15) =29a(16) =32a(17) =37a(18) =41a(19) =46a(20) =50a(21) =56a(22) =61a(23) =67a(24) =72a(25) =79a(26) =85a(27) =92a(28) =98a(29) =106