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Numbers n such that neither prime(n-1) nor prime(n+1) is of form 6k+1.
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%I #6 Nov 21 2013 12:50:00

%S 2,4,6,8,14,16,25,27,29,31,34,40,42,44,50,53,55,56,61,63,65,70,78,80,

%T 82,88,90,93,95,97,103,108,117,119,125,127,136,138,141,143,145,147,

%U 149,151,153,155,157,159,161,163,165,172,177,183,185,191,193,195,200,207

%N Numbers n such that neither prime(n-1) nor prime(n+1) is of form 6k+1.

%H Harvey P. Dale, <a href="/A173144/b173144.txt">Table of n, a(n) for n = 1..1000</a>

%F A000040(a(n))=A171817(m).

%e a(1)=2 because prime(2-1)=2 and prime(2+1)=5 are not of form 6k+1.

%t f6kQ[n_]:=And@@(!IntegerQ[(#-1)/6]&/@{Prime[n-1],Prime[n+1]}); Select[ Range[2,300],f6kQ] (* _Harvey P. Dale_, Feb 29 2012 *)

%Y Cf. A002476, A171817.

%K nonn,easy,less

%O 1,1

%A _Juri-Stepan Gerasimov_, Feb 11 2010

%E 1 removed by _Charles R Greathouse IV_, Mar 25 2010