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A111732
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Sum of the squares of the first n nonsquarefree numbers (A013929).
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0
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0, 16, 80, 161, 305, 561, 885, 1285, 1861, 2486, 3215, 3999, 5023, 6319, 7919, 9855, 11880, 14184, 16585, 19085, 21789, 24705, 27841, 31441, 35410, 39506, 44130, 49314, 54939, 60715, 67115, 73676, 80732, 88476, 96576, 105040, 114256, 123860
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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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Eric Weisstein's World of Mathematics, Squarefree.
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FORMULA
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a(n) ~ c * n^3, where c = Pi^4/(3*(Pi^2-6)^2) = 2.168428... . - Amiram Eldar, Jan 19 2024
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EXAMPLE
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a(10) = 4^2 + 8^2 + 9^2 + 12^2 + 16^2 + 18^2 + 20^2 + 24^2 + 25^2 + 27^2 = 3215.
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MATHEMATICA
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Accumulate[Select[Range[0, 100], ! SquareFreeQ[#] &]^2] (* Amiram Eldar, Jan 19 2024 *)
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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