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A145109
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a(n) = 2*n * core(2*n).
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1
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4, 4, 36, 16, 100, 36, 196, 16, 36, 100, 484, 144, 676, 196, 900, 64, 1156, 36, 1444, 400, 1764, 484, 2116, 144, 100, 676, 324, 784, 3364, 900, 3844, 64, 4356, 1156, 4900, 144, 5476, 1444, 6084, 400, 6724, 1764, 7396, 1936, 900, 2116, 8836, 576, 196, 100, 10404
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OFFSET
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1,1
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COMMENTS
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All terms are even squares (A016742).
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LINKS
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FORMULA
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MATHEMATICA
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a[1] = 4; a[n_] := 2*n * Times @@ (First[#]^Mod[Last[#], 2] & /@ FactorInteger[2*n]); Array[a, 50] (* Amiram Eldar, Sep 05 2020 *)
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PROG
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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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EXTENSIONS
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STATUS
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approved
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