Search: id:A007811
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%I A007811
%S A007811 1,10,19,82,148,187,208,325,346,565,943,1300,1564,1573,1606,1804,
%T A007811 1891,1942,2101,2227,2530,3172,3484,4378,5134,5533,6298,6721,
%U A007811 6949,7222,7726,7969,8104,8272,8881,9784,9913
%N A007811 Numbers n for which 10n+1, 10n+3, 10n+7 and 10n+9 are primes.
%H A007811 Charles Greathouse, <a href="b007811.txt">Table of n, a(n) for n = 1..10000</
               a>
%F A007811 A007811(n)=3*A014561(n)+1. [From Zak Seidov (zakseidov(AT)yahoo.com), 
               Sep 21 2009]
%p A007811 for n from 1 to 10000 do m := 10*n: if isprime(m+1) and isprime(m+3) 
               and isprime(m+7) and isprime(m+9) then print(n); fi: od: quit
%t A007811 Select[ Range[ 1, 10000, 3 ], PrimeQ[ 10*#+1 ] && PrimeQ[ 10*#+3 ] && 
               PrimeQ[ 10*#+7 ] && PrimeQ[ 10*#+9 ]& ]
%t A007811 Select[Range[15000], And @@ PrimeQ /@ ({1, 3, 7, 9} + 10#) &] (*Chandler*)
%Y A007811 Cf. A024912, A102338, A102342, A102700.
%Y A007811 Sequence in context: A023109 A033866 A146091 this_sequence A166706 A131495 
               A060630
%Y A007811 Adjacent sequences: A007808 A007809 A007810 this_sequence A007812 A007813 
               A007814
%K A007811 nonn
%O A007811 1,2
%A A007811 N. J. A. Sloane (njas(AT)research.att.com) and J. H. Conway (conway(AT)math.princeton.edu)

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