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Search: id:A025547
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| A025547 |
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Least common multiple of {1,3,5,...,2n-1}. |
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16
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| 1, 3, 15, 105, 315, 3465, 45045, 45045, 765765, 14549535, 14549535, 334639305, 1673196525, 5019589575, 145568097675, 4512611027925, 4512611027925, 4512611027925, 166966608033225, 166966608033225, 6845630929362225, 294362129962575675, 294362129962575675
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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This sequence coincides with the sequence f(n) = denominator of 1+1/3+1/5+1/7+...+1/(2n-1) iff n <= 38. But a(39) = 6414924694381721303722858446525, f(39) = 583174972216520118520259858775. - T. D. Noe (noe(AT)sspectra.com), Aug 04 2004
Coincides for n=1..42 with the denominators of a series for Pi*sqrt(2)/4, and then starts to differ. See A127676.
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LINKS
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T. D. Noe, Table of n, a(n) for n=1..200
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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MAPLE
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A025547:=proc(n) local i, t1; t1:=1; for i from 1 to n do t1:=lcm(t1, 2*i-1); od: t1; end;
f := n->denom(add(1/(2*k-1), k=0..n)); # a different sequence!
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CROSSREFS
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Cf. A007509, A025550, A075135. The numerators are in A074599.
Cf. A003418 (LCM of {1..n})
Sequence in context: A003276 A136092 A145624 this_sequence A088989 A001801 A067546
Adjacent sequences: A025544 A025545 A025546 this_sequence A025548 A025549 A025550
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KEYWORD
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easy,nice,nonn
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AUTHOR
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Clark Kimberling (ck6(AT)evansville.edu)
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