A162410 Numbers n such that 10*n + 3 and 10*n + 7 are prime.
0, 1, 4, 10, 16, 19, 22, 31, 46, 61, 64, 67, 82, 85, 88, 109, 121, 130, 142, 148, 166, 169, 178, 187, 199, 208, 220, 229, 247, 268, 283, 295, 316, 325, 334, 346, 361, 367, 379, 394, 400, 415, 451, 478, 481, 493, 523, 541, 550, 565, 592, 604, 673, 682, 724, 757
Offset: 1
Keywords
Examples
10*0 + 3 = 3 and 10*0 + 7 = 7 are prime, hence 0 is a term; 10*10 + 3 = 103 and 10*10 + 7 = 107 are prime, hence 10 is a term.
Crossrefs
Cf. A076746.
Programs
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Magma
[ n: n in [0..760] | IsPrime(10*n+3) and IsPrime(10*n+7) ]; // Klaus Brockhaus, Jul 07 2009
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Mathematica
f1[n_]:=10*n+3; f2[n_]:=10*n+7; lst={};Do[p1=f1[n];p2=f2[n];If[PrimeQ[p1]&&PrimeQ[p2],AppendTo[lst,n]],{n,0,2*6!}];lst Select[Range[0,1000],And@@PrimeQ[10#+{3,7}]&] (* Harvey P. Dale, May 11 2014 *)
Extensions
Edited and listed terms verified by Klaus Brockhaus, Jul 07 2009