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%I #6 May 10 2013 12:45:37
%S 1,2,1,3,4,20,5,35,56,504,70,770,3960,1144,1001,45045,80080,1361360,
%T 204204,184756,67184,470288,323323,7436429,27457584,228813200,
%U 106234700,2868336900,356948592,10351509168,145568097675,45581929575,85801279200
%N Denominator of sum of all elements M(i,j,k) = i*j/k, (i,j,k = 1..n). a(n) = Denominator[Sum[Sum[Sum[i*j/k,{i,1,n}],{j,1,n}],{k,1,n}]].
%F a(n) = Denominator[Sum[Sum[Sum[i*j/k, {i, 1, n}], {j, 1, n}], {k, 1, n}]]
%F a(n) = denominator of ((n^2+n)/2)^2*Sum(1/i, i=1..n). - _Vladeta Jovovic_, Oct 30 2004
%e Sum[M(i,j,k)] begins 1, 27/2, 66, 625/3, 2055/4, 21609/20, ... So a(2) = 2.
%t Table[ Denominator[ Sum[ i*j/k, {i, n}, {j, n}, {k, n}]], {n, 33}]
%Y Corresponding numerator is A099865
%Y Cf. A099865.
%K nonn
%O 1,2
%A _Alexander Adamchuk_, Oct 28 2004
%E More terms from _Robert G. Wilson v_, Nov 02 2004
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