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0, 2, 8, 23, 52, 107, 190, 324, 514, 781, 1128, 1604, 2192, 2962, 3896, 5026, 6372, 8030, 9940, 12243, 14874, 17899, 21324, 25324, 29772, 34850, 40496, 46827, 53798, 61687, 70244, 79852, 90348, 101842, 114312, 127946, 142576, 158700, 176048, 194788, 214812
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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0,2
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LINKS
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MATHEMATICA
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z[n_] := Sum[If[GCD[i, j] == 1, (n-i+1)(n-j+1), 0], {i, n}, {j, n}];
a[n_] := If[n == 0, 0, (z[n] + n^2 + 2n)/2];
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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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