A216307 Values of k such that 10*k+3 and 10*k+9 alone are prime between 10*k and 10*k+9.

2, 5, 8, 17, 23, 26, 35, 37, 38, 44, 50, 56, 59, 65, 73, 101, 110, 112, 122, 128, 143, 149, 154, 155, 161, 175, 197, 206, 233, 239, 254, 269, 290, 296, 308, 320, 331, 332, 353, 373, 392, 401, 407, 413, 425, 428, 464, 467, 479, 490, 499, 500, 511, 527, 530

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 + 3, 10*n + 9}, AppendTo[t, n]], {n, 0, 782}]; t (* T. D. Noe, Sep 04 2012 *)
Select[Range[800],Boole[PrimeQ[Range[10 #,10 #+9]]]=={0,0,0,1,0,0,0,0,0,1}&] (* Harvey P. Dale, Apr 23 2019 *)

Formula

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