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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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6
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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
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| Nathaniel Johnston, Table of n, a(n) for n = 0..10000
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MAPLE
| A049690 := proc(n) return add(numtheory[phi](2*k), k=1..n): end: seq(A049690(n), n=0..54); # Nathaniel Johnston, May 24 2011
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CROSSREFS
| a(n)=b(2n), where b=A049689. Bisections: A099958, A190815.
Sequence in context: A183859 A096228 A061571 * A080075 A007664 A114395
Adjacent sequences: A049687 A049688 A049689 * A049691 A049692 A049693
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KEYWORD
| nonn,easy
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AUTHOR
| Clark Kimberling (ck6(AT)evansville.edu)
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EXTENSIONS
| More terms from Vladeta Jovovic (vladeta(AT)eunet.rs), May 18 2001
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