This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A215473 #12 Aug 12 2012 19:02:07
%S A215473 0,0,1,2,2,2,3,4,4,5,7,10,11,16,23,28,43,62,106,177,309,483,795,1305,
%T A215473 2105,3525,5923,10096,17259,30004
%N A215473 Number of prime quadruples with smallest member < 2^n.
%C A215473 Prime quadruples (A007530) are numbers n such that n, n+2, n+6, n+8 are all prime.
%e A215473 a(3) = 1 because there is only one prime quadruple below 2^3, namely {5, 7, 11, 13}.
%e A215473 a(4) = 2 because there are two prime quadruples below 2^4: the aforementioned and {11, 13, 17, 19}.
%t A215473 (* First run program for A007530 *) Table[Length[Select[A007530, # < 2^n &]], {n, 14}] (* _Alonso del Arte_, Aug 12 2012 *)
%Y A215473 Cf. A050258, similar definition but with powers of 10 instead of 2.
%Y A215473 Cf. A007530, A014561, A112540.
%Y A215473 Cf. A033843, A007053.
%K A215473 nonn
%O A215473 1,4
%A A215473 _Alex Ratushnyak_, Aug 12 2012