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%I #6 Nov 21 2013 12:48:17
%S 0,0,0,1,6,16,38,70,124,200,314,452,644,890,1216,1592,2068,2624,3312,
%T 4094,5042,6138,7438,8844,10488,12348,14496,16796,19422,22314,25590,
%U 29158,33168,37530,42400,47526,53204,59356,66132,73226,81004,89338,98436,108086,118582
%N Sum_{k=2..n} min(k,n-k)*phi(k)*(n-k).
%D J. O'Rourke, Art Gallery Theorems and Algorithms, Oxford Univ. Press, 1987, p. 222.
%t Table[Sum[Min[k,n-k]EulerPhi[k](n-k),{k,2,n}],{n,0,50}] (* _Harvey P. Dale_, May 02 2012 *)
%K nonn
%O 0,5
%A _N. J. A. Sloane_, Feb 17 2004
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