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Search: id:A122551
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| A122551 |
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Denominators of the coefficients of the series for InverseErf[x]. |
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+0
1
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| 2, 24, 960, 80640, 11612160, 2554675200, 797058662400, 334764638208000, 182111963185152000, 124564582818643968000, 104634249567660933120000, 105889860562472864317440000, 127067832674967437180928000000
(list; graph; listen)
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OFFSET
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0,1
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COMMENT
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Note: the term in x^11 in the series expansion above has a common factor of 7 between the numerator and denominator and is usually written 34807/364953600. The common factor of 7 occurs at n=6, 9, 12 etc. The sequence of the coefficients can be generated by combining this series with A002067
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FORMULA
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a(n) = (2*n+1)!*2^(n+1)
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EXAMPLE
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InverseErf[x] = (1/2*sqrt(Pi))*x+(1/24*Pi^(3/2))*x^3+(7/960*Pi^(5/2))*x^5+(127/80640*Pi^(7/2))*x^7+(4369/11612160*Pi^(9/2))*x^9+(243649/2554675200*Pi^(11/2))*x^11+...
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MAPLE
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denominators:=[seq((2*n+1)!*2^(n+1), n=0..14)]; a:=proc(n) if(n < 2) then RETURN(1) fi; sum('binomial(2*n, 2*k)*a(k)*a(n-k-1)', 'k'=0..n-1); end; numerators:=[seq(a(n), n=0..14)];
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CROSSREFS
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Cf. A002067 and A092676.
Sequence in context: A015212 A012228 A062029 this_sequence A136524 A137887 A094050
Adjacent sequences: A122548 A122549 A122550 this_sequence A122552 A122553 A122554
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KEYWORD
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easy,nonn
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AUTHOR
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Marcus Blackburn (marcus.blackburn(AT)dial.pipex.com), Sep 20 2006
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