A216304 Values of k such that 10*k+1 and 10*k+7 alone are prime between 10*k and 10*k+9.

3, 6, 15, 25, 27, 33, 54, 57, 60, 75, 94, 97, 99, 118, 123, 129, 132, 136, 162, 174, 186, 190, 201, 213, 228, 234, 235, 237, 241, 244, 255, 267, 279, 285, 306, 318, 330, 351, 354, 363, 369, 402, 405, 439, 444, 445, 456, 459, 465, 487, 495, 508, 510, 538

Offset: 1

Author

V. Raman, Sep 03 2012

Keywords

• nonn

Links

• V. Raman, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A032352, A007811, A078494.

Programs

Mathematica

t = {}; Do[ps = Select[Range[10*n, 10*n + 9], PrimeQ]; If[ps == {10*n + 1, 10*n + 7}, AppendTo[t, n]], {n, 0, 699}]; t (* T. D. Noe, Sep 04 2012 *)
Select[Range[600],Boole[PrimeQ[Range[10 #,10 #+9]]]=={0,1,0,0,0,0,0,1,0,0}&] (* Harvey P. Dale, Sep 15 2016 *)

Formula

a(n) >> n log^2 n. - Charles R Greathouse IV, Sep 07 2012