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Search: id:A090585
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| A090585 |
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Numerator of Sum/Product of first n numbers. |
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+0
8
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| 1, 3, 1, 5, 1, 7, 1, 1, 1, 11, 1, 13, 1, 1, 1, 17, 1, 19, 1, 1, 1, 23, 1, 1, 1, 1, 1, 29, 1, 31, 1, 1, 1, 1, 1, 37, 1, 1, 1, 41, 1, 43, 1, 1, 1, 47, 1, 1, 1, 1, 1, 53, 1, 1, 1, 1, 1, 59, 1, 61, 1, 1, 1, 1, 1, 67, 1, 1, 1, 71, 1, 73, 1, 1, 1, 1, 1, 79, 1, 1, 1, 83, 1
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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a(n) = A000217(n)/A069268(n);
a(n) = A089026(n+1) for n>1.
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FORMULA
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Also for n>1 a(n) is a numerator of determinant of (n-1) X (n-1) matrix with M(i,j) = (i+2)/(i+1) if i=j otherwise 1. E.g. a(2) = Numerator[Det[{{3/2}}]] = Numerator[3/2] = 3. a(3) = Numerator[Det[{{3/2,1},{1,4/3}}]] = Numerator[1/1] = 1. a(4) = Numerator[Det[{{3/2,1,1},{1,4/3,1},{1,1,5/4}}]] = Numerator[5/12] = 5. - Alexander Adamchuk (alex(AT)kolmogorov.com), May 26 2006
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CROSSREFS
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Denominator=A090586.
Cf. A118679.
Sequence in context: A029652 A129510 A087913 this_sequence A009001 A093178 A093411
Adjacent sequences: A090582 A090583 A090584 this_sequence A090586 A090587 A090588
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KEYWORD
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nonn,frac
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AUTHOR
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Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Dec 03 2003
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