Squares of the form p1 - 1 where p1 is a lower twin prime.

Terms

a(0) =4a(1) =16a(2) =100a(3) =196a(4) =5476a(5) =8836a(6) =16900a(7) =17956a(8) =21316a(9) =25600a(10) =52900a(11) =65536a(12) =106276a(13) =115600a(14) =122500a(15) =164836a(16) =184900a(17) =193600a(18) =220900a(19) =341056a(20) =401956a(21) =470596a(22) =490000a(23) =495616a(24) =614656a(25) =739600a(26) =846400a(27) =972196a(28) =1110916a(29) =1144900