a(n) = 80*n^2 - 1.

Terms

a(0) =79a(1) =319a(2) =719a(3) =1279a(4) =1999a(5) =2879a(6) =3919a(7) =5119a(8) =6479a(9) =7999a(10) =9679a(11) =11519a(12) =13519a(13) =15679a(14) =17999a(15) =20479a(16) =23119a(17) =25919a(18) =28879a(19) =31999a(20) =35279a(21) =38719a(22) =42319a(23) =46079a(24) =49999a(25) =54079a(26) =58319a(27) =62719a(28) =67279a(29) =71999