Ceiling(Pi*n^2).

Terms

a(0) =0a(1) =4a(2) =13a(3) =29a(4) =51a(5) =79a(6) =114a(7) =154a(8) =202a(9) =255a(10) =315a(11) =381a(12) =453a(13) =531a(14) =616a(15) =707a(16) =805a(17) =908a(18) =1018a(19) =1135a(20) =1257a(21) =1386a(22) =1521a(23) =1662a(24) =1810a(25) =1964a(26) =2124a(27) =2291a(28) =2464a(29) =2643