Number of twins of prime quadruples < 10^n.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =4a(7) =5a(8) =18a(9) =65a(10) =267a(11) =1238a(12) =6196a(13) =33480a(14) =187932a(15) =1095882a(16) =6629232