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Search: id:A130823
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| A130823 |
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Each odd number appears thrice. |
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+0
2
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| 1, 1, 1, 3, 3, 3, 5, 5, 5, 7, 7, 7, 9, 9, 9, 11, 11, 11, 13, 13, 13, 15, 15, 15, 17, 17, 17, 19, 19, 19, 21, 21, 21, 23, 23, 23, 25, 25, 25, 27, 27, 27, 29, 29, 29, 31, 31, 31, 33, 33, 33, 35, 35, 35, 37, 37, 37, 39, 39, 39, 41, 41, 41, 43, 43, 43, 45, 45, 45, 47, 47, 47, 49, 49
(list; graph; listen)
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OFFSET
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1,4
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COMMENT
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Partial sums of 1,0,0,2,0,0,2,0,0,2,0,0,... . - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007
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FORMULA
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G.f.: x(1+x^3)/[(1-x)(1-x^3)]. - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007
Euler transform of length 6 sequence [ 1, 0, 2, 0, 0, -1]. - Michael Somos Aug 16 2007
a(n+3) = a(n)+2. a(1-n) = -a(n). - Michael Somos Aug 16 2007
a(n)=-1+Sum_{k=0..n}{(2/9)*[ -2*(k mod 3)+((k+1) mod 3)+4*((k+2) mod 3)} - Paolo P. Lava (ppl(AT)spl.at), Aug 29 2007
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MAPLE
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G:=x*(1+x^3)/((1-x)*(1-x^3)): Gser:=series(G, x=0, 82): seq(coeff(Gser, x, n), n= 1..75); - Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007
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PROGRAM
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(PARI) {a(n) = (n-1)\3*2+1} /* Michael Somos Aug 16 2007 */
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CROSSREFS
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Sequence in context: A130175 A101290 A080605 this_sequence A101435 A077886 A096015
Adjacent sequences: A130820 A130821 A130822 this_sequence A130824 A130825 A130826
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KEYWORD
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nonn
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AUTHOR
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Paul Curtz (bpcrtz(AT)free.fr), Jul 17 2007
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EXTENSIONS
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More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007
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