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A049690
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a(n) = Sum_{k=1..n} phi(2*k), where phi = Euler totient function, cf. A000010.
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10
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0, 1, 3, 5, 9, 13, 17, 23, 31, 37, 45, 55, 63, 75, 87, 95, 111, 127, 139, 157, 173, 185, 205, 227, 243, 263, 287, 305, 329, 357, 373, 403, 435, 455, 487, 511, 535, 571, 607, 631, 663, 703, 727, 769, 809, 833, 877, 923, 955, 997, 1037, 1069, 1117, 1169, 1205
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OFFSET
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0,3
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LINKS
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FORMULA
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MAPLE
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MATHEMATICA
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PROG
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CROSSREFS
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KEYWORD
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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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