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Search: id:A141726
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| A141726 |
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Sawtooth with period length 9: repeat 8, 7, 6, 5, 4, 3, 2, 1, 0. |
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+0
3
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| 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3, 2, 1, 0, 8, 7, 6, 5, 4, 3
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Consider the sequence c(n) = c(n+9) = (10*A000027(2*n) + 3*A000027(2*n+1)) mod 9 = (8n+3) mod 9.
Then a(n) = c(n+3).
Also the continued fraction expansion of (23342+5*sqrt(44403565))/6961.
Also the decimal expansion of 973936900/111111111.
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FORMULA
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a(n)= a(n-9). G.f.: -x*(8+7*x+6*x^2+5*x^3+4*x^4+3*x^5+2*x^6+x^7)/((x-1)*(1+x+x^2)*(x^6+x^3+1)).
a(n)=(2/9)*{(-7/2)*(n mod 9)+[(n+1) mod 9] + [(n+2) mod 9] + [(n+3) mod 9] + [(n+4) mod 9]+[(n+5) mod 9]+[(n+6) mod 9]+[(n+7) mod 9]+[(n+8) mod 9]}, with n>=0 [From Paolo P. Lava (ppl(AT)spl.at), Sep 29 2008]
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CROSSREFS
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Cf. A010878.
Sequence in context: A138472 A022964 A023450 this_sequence A031310 A104347 A031311
Adjacent sequences: A141723 A141724 A141725 this_sequence A141727 A141728 A141729
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KEYWORD
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nonn,easy
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AUTHOR
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Paul Curtz (bpcrtz(AT)free.fr), Sep 13 2008
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EXTENSIONS
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Index in c-sequence corrected by R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 11 2009
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