a(n) = (prime(n)-1)*(prime(n)+1).

Terms

a(0) =3a(1) =8a(2) =24a(3) =48a(4) =120a(5) =168a(6) =288a(7) =360a(8) =528a(9) =840a(10) =960a(11) =1368a(12) =1680a(13) =1848a(14) =2208a(15) =2808a(16) =3480a(17) =3720a(18) =4488a(19) =5040a(20) =5328a(21) =6240a(22) =6888a(23) =7920a(24) =9408a(25) =10200a(26) =10608a(27) =11448a(28) =11880a(29) =12768