|
%I #21 Feb 27 2021 03:58:31
%S 11,29,47,83,101,127,137,149,173,191,227,263,277,281,317,353,389,443,
%T 461,479,509,541,569,577,587,607,641,659,677,727,821,827,839,857,877,
%U 911,929,947,977,983,1019,1031,1091,1109,1129,1163,1181,1217,1277,1289
%N Primes p such that p-2 is not squarefree.
%C This sequence is infinite and its relative density in the sequence of the primes is equal to 1 - 2 * Product_{p prime} (1-1/(p*(p-1)) = 1 - 2 * A005596 = 0.252088... - _Amiram Eldar_, Feb 27 2021
%H Harvey P. Dale, <a href="/A049229/b049229.txt">Table of n, a(n) for n = 1..1000</a>
%t Select[Prime[Range[2,300]],!SquareFreeQ[#-2]&] (* _Harvey P. Dale_, Nov 14 2012 *)
%o (PARI) isok(p) = (p>2) && isprime(p) && !issquarefree(p-2); \\ _Michel Marcus_, May 14 2018
%Y Cf. A005596, A013929, A049231, A049232.
%K nonn
%O 1,1
%A _Labos Elemer_
|
