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A282380 Number of ways to write n as a sum of two unordered nonsquarefree numbers. 1

%I

%S 0,0,0,0,0,0,0,1,0,0,0,1,1,0,0,2,1,1,0,2,1,1,0,3,1,1,1,3,2,1,1,4,2,2,

%T 1,6,2,1,1,5,2,1,2,5,3,1,1,6,3,2,1,7,4,4,1,7,4,4,2,7,4,3,3,8,4,3,3,9,

%U 4,4,2,12,4,4,3,10,5,3,4,10,6,3,3,11,5,3,3,12,5,6,3,11,6,5,4,12,5,5,7,14,5,6,5,14,5,6

%N Number of ways to write n as a sum of two unordered nonsquarefree numbers.

%H Altug Alkan, <a href="/A282380/b282380.txt">Table of n, a(n) for n = 1..10000</a>

%e a(16) = 2 because 16 = 4 + 12 and 16 = 8 + 8 are only corresponding solutions.

%o (PARI) a(n) = sum(k=1, n\2, !issquarefree(k) && !issquarefree(n-k));

%Y Cf. A013929, A071068.

%K nonn

%O 1,16

%A _Altug Alkan_, Feb 13 2017

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