Partial sums of ceiling(n^2/2) (A000982).

Terms

a(0) =0a(1) =1a(2) =3a(3) =8a(4) =16a(5) =29a(6) =47a(7) =72a(8) =104a(9) =145a(10) =195a(11) =256a(12) =328a(13) =413a(14) =511a(15) =624a(16) =752a(17) =897a(18) =1059a(19) =1240a(20) =1440a(21) =1661a(22) =1903a(23) =2168a(24) =2456a(25) =2769a(26) =3107a(27) =3472a(28) =3864a(29) =4285