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Search: id:A130045
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| A130045 |
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Denominator of polynomial a[1]=1, a[2]->1+1/(x*a[1]), a[3]->1+1/(2*x*a[2]), a[4]->1+1/(3*x*a[3]),.. giving 1,(1+x)/x,(3+2*x)/(2*(1+x)),(2+11*x+6*x^2)/(3*x*(3+2*x)), .. at x-> -1. Absolute values are equal to A067078(n)/n. |
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+0
1
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| 1, 1, 4, -9, -20, 55, 210, -1085, -7000, 53235, 462350, -4500265, -48454980, 571411295, 7321388410, -101249656725, -1502852293040, 23827244817355, 401839065437670, -7182224591785985, -135607710526966300, 2696935204638786615, 56349204870460046930, -1234002202313888987245
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OFFSET
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1,3
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COMMENT
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The iterated form (see Mma line) links some seemingly disparate sequences.
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FORMULA
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A067078 has recurrence a(1) = 1, a(2) = 2, a(n) = (n-1)*a(n-1) - (n-2)*a(n-2).
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MATHEMATICA
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Denominator[Together[k=1; NestList[1+1/((k++)x #)&, x, 24]]]/.x->(-1)
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CROSSREFS
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Cf. A067078, A052169, A002467, A001053, A093858.
Adjacent sequences: A130042 A130043 A130044 this_sequence A130046 A130047 A130048
Sequence in context: A109110 A108870 A111587 this_sequence A038805 A120535 A033944
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KEYWORD
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frac,sign
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AUTHOR
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Wouter Meeussen (wouter.meeussen(AT)pandora.be), May 02 2007
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