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A155141 Primes p such that both p-+4 are squarefree. 5

%I #12 Jul 06 2016 02:32:34

%S 2,3,7,11,17,19,37,43,47,61,73,83,89,97,101,107,109,127,137,163,181,

%T 191,197,199,223,227,233,251,263,269,277,281,307,313,317,331,349,353,

%U 389,397,431,433,439,443,449,457,461,467,487,523,541,547,557,569,577,587

%N Primes p such that both p-+4 are squarefree.

%H John Cerkan, <a href="/A155141/b155141.txt">Table of n, a(n) for n = 1..10000</a>

%t <<NumberTheory`NumberTheoryFunctions` lst={};Do[p=Prime[n];If[SquareFreeQ[p-4]&&SquareFreeQ[p+4],AppendTo[lst,p]],{n,6!}];lst

%t Select[Prime[Range[150]],AllTrue[#+{4,-4},SquareFreeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jun 15 2016 *)

%o (PARI) lista(nn) = forprime(p=2, nn, if (issquarefree(p-4) && issquarefree(p+4), print1(p, ", "))); \\ _Michel Marcus_, Jul 06 2016

%Y Cf. A153213, A049282, A155139, A155140, A155142.

%K nonn

%O 1,1

%A _Vladimir Joseph Stephan Orlovsky_, Jan 21 2009

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Last modified August 19 22:28 EDT 2024. Contains 375310 sequences. (Running on oeis4.)