OFFSET
1,4
COMMENTS
Prime quadruples (A007530) are numbers n such that n, n+2, n+6, n+8 are all prime.
EXAMPLE
a(3) = 1 because there is only one prime quadruple below 2^3, namely {5, 7, 11, 13}.
a(4) = 2 because there are two prime quadruples below 2^4: the aforementioned and {11, 13, 17, 19}.
MATHEMATICA
(* First run program for A007530 *) Table[Length[Select[A007530, # < 2^n &]], {n, 14}] (* Alonso del Arte, Aug 12 2012 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Alex Ratushnyak, Aug 12 2012
STATUS
approved