Search: id:A066025
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%I A066025
%S A066025 5,12,14,70,88,125,180,204,206,220,957,1253,1334,1364,1634,1673,1750,
%T A066025 1888,1919,2685,2759,2958,2974,3127,4364,5191,7615,8142,8632,9114,
%U A066025 11219,12000,12035,14664,14841,18414,18762,18873,19358,20118
%N A066025 Numbers n such that GCD(Sigma(n), Sigma(n+1)) > n.
%H A066025 Harry J. Smith, <a href="b066025.txt">Table of n, a(n) for n=1,...,1000</
               a>
%e A066025 GCD(Sigma(12), Sigma(13)) = GCD(28, 14) = 14 > 12.
%t A066025 Select[Range[1, 10^5], GCD[DivisorSigma[1, # ], DivisorSigma[ 1, # + 
               1]] > # &]
%o A066025 (PARI) { n=0; s=1; for (m=1, 10^9, t=s; s=sigma(m + 1); if (gcd(t, s) 
               > m, write("b066025.txt", n++, " ", m); if (n==1000, return)) ) } 
               [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Nov 07 2009]
%Y A066025 Cf. A000010.
%Y A066025 Sequence in context: A014156 A114073 A037007 this_sequence A009824 A087090 
               A161756
%Y A066025 Adjacent sequences: A066022 A066023 A066024 this_sequence A066026 A066027 
               A066028
%K A066025 nonn
%O A066025 1,1
%A A066025 Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 11 2001
%E A066025 Definition and EXAMPLE edited by Harry J. Smith (hjsmithh(AT)sbcglobal.net), 
               Nov 07 2009

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