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A130823
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Each odd number appears thrice.
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3
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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; refs; listen; history; internal format)
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OFFSET
| 1,4
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COMMENTS
| Partial sums of 1,0,0,2,0,0,2,0,0,2,0,0,... . - Emeric Deutsch, Jul 23 2007
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LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..10000
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FORMULA
| G.f.: x*(1+x^3)/((1-x)*(1-x^3)). - Emeric Deutsch, 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=1..n}{(2/9)*[(k mod 3)+4*((k+1) mod 3)-2*((k+2) mod 3)]}, with n>=1 - Paolo P. Lava, Aug 29 2007, Aug 22 2009
a(n) = floor((n-1)/3)*2+1 - Michael Somos' formula suggested by Johannes Meijer (meijgia(AT)hotmail.com) [From Paolo P. Lava, Aug 21 2009]
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MAPLE
| 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, Jul 23 2007
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PROG
| (PARI) {a(n) = (n-1)\3*2+1} /* Michael Somos Aug 16 2007 */
(MAGMA) [(Floor((n-1)/3)*2+1): n in [1..80]]; // Vincenzo Librandi, Aug 10 2011
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CROSSREFS
| Sequence in context: A200266 A101290 A080605 * A101435 A077886 A096015
Adjacent sequences: A130820 A130821 A130822 * A130824 A130825 A130826
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KEYWORD
| nonn
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AUTHOR
| Paul Curtz (bpcrtz(AT)free.fr), Jul 17 2007
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EXTENSIONS
| More terms from Emeric Deutsch (deutsch(AT)duke.poly.edu), Jul 23 2007
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