Average of twin prime pairs.

Terms

a(0) =4a(1) =6a(2) =12a(3) =18a(4) =30a(5) =42a(6) =60a(7) =72a(8) =102a(9) =108a(10) =138a(11) =150a(12) =180a(13) =192a(14) =198a(15) =228a(16) =240a(17) =270a(18) =282a(19) =312a(20) =348a(21) =420a(22) =432a(23) =462a(24) =522a(25) =570a(26) =600a(27) =618a(28) =642a(29) =660