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%I #12 Dec 22 2024 12:12:50
%S 0,3,8,12,24,59,48,48,72,171,120,236,168,339,416,192,288,531,360,684,
%T 824,843,528,944,600,1179,648,1356,840,2339,960,768,2048,2019,2376,
%U 2124,1368,2523,2864,2736,1680,4619,1848,3372,3744,3699,2208
%N a(n) = n^2 * Sum_{primes p dividing n} (1 - 1/p^2).
%H Harry J. Smith, <a href="/A065970/b065970.txt">Table of n, a(n) for n = 1..1000</a>
%o (PARI) a(n) = { my(s=0); foreach(factor(n)[,1], p, s+=1 - 1/p^2); n^2*s } \\ _Harry J. Smith_, Nov 05 2009
%Y Cf. A065967, A065968, A065969.
%K nonn
%O 1,2
%A _N. J. A. Sloane_, Dec 09 2001