Prime(prime(n))^2-1.

Terms

a(0) =8a(1) =24a(2) =120a(3) =288a(4) =960a(5) =1680a(6) =3480a(7) =4488a(8) =6888a(9) =11880a(10) =16128a(11) =24648a(12) =32040a(13) =36480a(14) =44520a(15) =58080a(16) =76728a(17) =80088a(18) =109560a(19) =124608a(20) =134688a(21) =160800a(22) =185760a(23) =212520a(24) =259080a(25) =299208a(26) =316968a(27) =344568a(28) =358800a(29) =380688