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

Terms

a(0) =0a(1) =1a(2) =2a(3) =10a(4) =16a(5) =39a(6) =54a(7) =100a(8) =128a(9) =205a(10) =250a(11) =366a(12) =432a(13) =595a(14) =686a(15) =904a(16) =1024a(17) =1305a(18) =1458a(19) =1810a(20) =2000a(21) =2431a(22) =2662a(23) =3180a(24) =3456a(25) =4069a(26) =4394a(27) =5110a(28) =5488a(29) =6315