A215473 Number of prime quadruples with smallest member < 2^n.

0, 0, 1, 2, 2, 2, 3, 4, 4, 5, 7, 10, 11, 16, 23, 28, 43, 62, 106, 177, 309, 483, 795, 1305, 2105, 3525, 5923, 10096, 17259, 30004

Offset

1,4

Comments

Prime quadruples (A007530) are numbers n such that n, n+2, n+6, n+8 are all prime.

Links

Table of n, a(n) for n=1..30.

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

Cf. A050258, similar definition but with powers of 10 instead of 2.

Cf. A007530, A014561, A112540.

Cf. A033843, A007053.

Sequence in context: A274201 A079398 A225499 * A071988 A301337 A302404

Adjacent sequences: A215470 A215471 A215472 * A215474 A215475 A215476

Keyword

nonn

Author

Alex Ratushnyak, Aug 12 2012

Status

approved