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Search: id:A114705
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%I A114705
%S A114705 6,14,48,98,372,868,2784,7236,27744,64708,215040,541156,1947840,5168548,
%T A114705 23046144,43129476,155189760,444228512,1398675600,3623742864,
%U A114705 14636428992,33799504228,113272236000,299806597512,1154553386688
%N A114705 Sum of divisors of 2^n + 3^n.
%C A114705 The terms are never squares. For n>=2, 2^n+3^n falls into a pattern of 
               quadratic non-residues, taken modulo 20: 13, 15, 17, 15, 13, 15, 
               17, 15, ... - Jack Brennen, Dec 25 2005
%C A114705 a(n) is always even because 2^n+3^n is never a quadratic residue modulo 
               15. - Jose Brox (tautocrona(AT)terra.es), Dec 27 2005
%e A114705 a(3)=48 because 2^3+3^3=8+27=35 has divisors 1,5,7,35 sum of which is 
               48.
%t A114705 Table[DivisorSigma[1, 2^n+3^n], {n, 1, 30}]
%Y A114705 Cf. A000203.
%Y A114705 Sequence in context: A093369 A130443 A005515 this_sequence A107301 A118432 
               A032404
%Y A114705 Adjacent sequences: A114702 A114703 A114704 this_sequence A114706 A114707 
               A114708
%K A114705 nonn
%O A114705 1,1
%A A114705 Zak Seidov (zakseidov(AT)yahoo.com), Dec 26 2005

    
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Last modified December 5 23:38 EST 2009. Contains 170428 sequences.


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