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A065368
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Alternating sum of ternary digits in n. Replace 3^k with (-1)^k in ternary expansion of n.
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2
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0, 1, 2, -1, 0, 1, -2, -1, 0, 1, 2, 3, 0, 1, 2, -1, 0, 1, 2, 3, 4, 1, 2, 3, 0, 1, 2, -1, 0, 1, -2, -1, 0, -3, -2, -1, 0, 1, 2, -1, 0, 1, -2, -1, 0, 1, 2, 3, 0, 1, 2, -1, 0, 1, -2, -1, 0, -3, -2, -1, -4, -3, -2, -1, 0, 1, -2, -1, 0, -3, -2, -1, 0, 1, 2, -1, 0, 1, -2, -1, 0, 1, 2, 3, 0, 1, 2, -1, 0, 1, 2, 3, 4, 1, 2, 3, 0, 1, 2, 3, 4, 5, 2, 3
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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COMMENTS
| Notation: (3)[n](-1)
Fixed point of the morphism 0-> 0,1,2 ; 1-> -1,0,1 ; 2-> -2,-1,0 ; ...; n-> -n,-n+1,-n+2 . - From DELEHAM Philippe, Oct 22 2011.
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FORMULA
| a(n)=Sum_k>=0 {A030341(n,k)*(-1)^k}. - From DELEHAM Philippe, Oct 22 201.
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EXAMPLE
| 15 = +1(9)+2(3)+0(1) -> +1(+1)+2(-1)+0(+1) = -1 = a(15)
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CROSSREFS
| Cf. A030341, A053735, A065359, A065364
Sequence in context: A118822 A054848 A194525 * A010751 A194523 A180714
Adjacent sequences: A065365 A065366 A065367 * A065369 A065370 A065371
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KEYWORD
| base,easy,sign
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AUTHOR
| Marc LeBrun (mlb(AT)well.com), Oct 31 2001
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EXTENSIONS
| Initial 0 added by DELEHAM Philippe, Oct 22 2011.
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