Number of prime quadruples with smallest member < 2^n.

Terms

a(0) =0a(1) =0a(2) =1a(3) =2a(4) =2a(5) =2a(6) =3a(7) =4a(8) =4a(9) =5a(10) =7a(11) =10a(12) =11a(13) =16a(14) =23a(15) =28a(16) =43a(17) =62a(18) =106a(19) =177a(20) =309a(21) =483a(22) =795a(23) =1305a(24) =2105a(25) =3525a(26) =5923a(27) =10096a(28) =17259a(29) =30004