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A131136
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Denominator of (exponential) expansion of log((x/2-1)/(x-1)).
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3
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1, 2, 4, 4, 8, 4, 8, 8, 16, 4, 8, 8, 16, 8, 16, 16, 32, 4, 8, 8, 16, 8, 16, 16, 32, 8, 16, 16, 32, 16, 32, 32, 64, 4, 8, 8, 16, 8, 16, 16, 32, 8, 16, 16, 32, 16, 32, 32, 64, 8, 16, 16, 32, 16, 32, 32, 64, 16, 32, 32, 64, 32, 64, 64, 128, 4, 8, 8, 16, 8, 16, 16, 32, 8, 16, 16
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| a(n+1)=2^A063787(n). a(n+1)=A001316(n)/2. - Stephen Crowley (crow(AT)crowlogic.net), Aug 25 2008
Also, 1 followed by A117973. [From Omar E. Pol (info(AT)polprimos.com), Dec 11 2010]
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FORMULA
| a(n)=0^n+n+sum((-1)^(1+binomial(n-1,k)),k=0..n-1) - Stephen Crowley (crow(AT)crowlogic.net), Aug 25 2008
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EXAMPLE
| Contribution from Omar E. Pol (info(AT)polprimos.com), Jun 14 2009, Dec 11 2010: (Start)
May be written as a triangle by using the Crowley formula with A063787:
.1;
.2;
.4,4;
.8,4,8,8;
.16,4,8,8,16,8,16,16;
.32,4,8,8,16,8,16,16,32,8,16,16,32,16,32,32;
.64,4,8,8,16,8,16,16,32,8,16,16,32,16,32,32,64,8,16,16,32,16,32,32,64,16,...
Also
1,
2,
4,
4,8,
4,8,8,16,
4,8,8,16,8,16,16,32,
4,8,8,16,8,16,16,32,8,16,16,32,16,32,32,64,
4,8,8,16,8,16,16,32,8,16,16,32,16,32,32,64,8,16,16,32,16,32,32,64,16,32,...
(End)
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MAPLE
| a(n)=abs(op(1, numer(expand(Zeta(2n)/Zeta(1-2n))))) - Stephen Crowley (crow(AT)crowlogic.net), Aug 25 2008
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CROSSREFS
| Cf. A001316, A131135.
Cf. A063787.
Cf. A000079, A117973. [From Omar E. Pol (info(AT)polprimos.com), Jun 14 2009, Dec 11 2010]
Sequence in context: A117215 A011173 A162943 * A117973 A140434 A107748
Adjacent sequences: A131133 A131134 A131135 * A131137 A131138 A131139
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KEYWORD
| nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Jun 17 2007
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