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Numbers n such that 10*n + 3 and 10*n + 7 are prime.
0

%I #9 Sep 08 2022 08:45:46

%S 0,1,4,10,16,19,22,31,46,61,64,67,82,85,88,109,121,130,142,148,166,

%T 169,178,187,199,208,220,229,247,268,283,295,316,325,334,346,361,367,

%U 379,394,400,415,451,478,481,493,523,541,550,565,592,604,673,682,724,757

%N Numbers n such that 10*n + 3 and 10*n + 7 are prime.

%e 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.

%t 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

%t Select[Range[0,1000],And@@PrimeQ[10#+{3,7}]&] (* _Harvey P. Dale_, May 11 2014 *)

%o (Magma) [ n: n in [0..760] | IsPrime(10*n+3) and IsPrime(10*n+7) ]; // _Klaus Brockhaus_, Jul 07 2009

%Y Cf. A076746.

%K nonn

%O 1,3

%A _Vladimir Joseph Stephan Orlovsky_, Jul 02 2009

%E Edited and listed terms verified by _Klaus Brockhaus_, Jul 07 2009

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Last modified September 23 04:44 EDT 2024. Contains 376142 sequences. (Running on oeis4.)