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A331775
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a(n) = Sum_{-n<i<n, -n<j<n, gcd{i,j}=3} (n-|i|)*(n-|j|)/4.
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1
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0, 0, 0, 5, 14, 27, 52, 85, 126, 197, 284, 387, 534, 705, 900, 1187, 1514, 1881, 2328, 2823, 3366, 4095, 4896, 5769, 6818, 7955, 9180, 10667, 12266, 13977, 15928, 18007, 20214, 22899, 25752, 28773, 32114, 35639, 39348, 43733, 48350, 53199, 58544
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OFFSET
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1,4
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LINKS
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MAPLE
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VR := proc(m, n, q) local a, i, j; a:=0;
for i from -m+1 to m-1 do for j from -n+1 to n-1 do
if gcd(i, j)=q then a:=a+(m-abs(i))*(n-abs(j)); fi; od: od: a; end;
[seq(VR(n, n, 3)/4, n=1..50)];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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