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Search: id:A127852
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%I A127852
%S A127852 1,3,10,19,24,30,43,51,58,62,73,75,82,94,101,106,115,116,118,128,138,
%T A127852 147,149,159,160,163,167,172,183,186,190,191,195,201,211,214,219,249,
%U A127852 250,252,253,260,266,272,274,277,279,283,290,294,296,306,309,310,318
%N A127852 Numbers n such that A118679(n) = 1.
%C A127852 A118679[ a(n) ] = 1, where A118679(n) = {1, 2, 1, 13, 19, 13, 17, 43, 
               53, 1, 19, ...} = Absolute value of numerator of determinant of n 
               X n matrix with M(i,j) = i/(i+1) if i=j otherwise 1. A118679(n) = 
               Numerator[ (n^2+3n-2)/(2(n+1)!) ] = Numerator[ ((2n+3)^2-17)/(4(n+1)!) 
               ].
%F A127852 An integer n is in this sequence iff all prime divisors of n^2+3n-2 do 
               not exceed n+1 and n^2+3n-2 is not of the form 2*p^2 for some prime 
               p. [From Max Alekseyev (maxale(AT)gmail.com), Jun 02 2009]
%t A127852 Select[Range[1000],Numerator[(#^2+3#-2)/(2(#+1)!)]==1&]
%Y A127852 Cf. A118679, A118680, A127853.
%Y A127852 Sequence in context: A051938 A074893 A074178 this_sequence A064027 A028878 
               A010896
%Y A127852 Adjacent sequences: A127849 A127850 A127851 this_sequence A127853 A127854 
               A127855
%K A127852 nonn
%O A127852 1,2
%A A127852 Alexander Adamchuk (alex(AT)kolmogorov.com), Feb 03 2007

    
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Last modified December 20 00:58 EST 2009. Contains 171054 sequences.


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