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A063023
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Reversion of y - y^2 - y^4 - y^5.
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0
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0, 1, 1, 2, 6, 21, 77, 292, 1143, 4592, 18821, 78364, 330512, 1409149, 6063526, 26298592, 114849110, 504595293, 2228824203, 9891723114, 44087704836, 197255893945, 885630834120, 3988872011820, 18017892014655
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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LINKS
| Index entries for reversions of series
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FORMULA
| a(n)=sum(k=0..n-1, (sum(j=floor((n-k-1)/3)..floor((n-k-1)/2), binomial(j,n-k-2*j-1)*binomial(k,j)))*binomial(n+k-1,n-1))/n, n>0, a(0)=0. [From Vladimir Kruchinin kru(AT)ie.tusur.ru, May 26 2011]
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MATHEMATICA
| CoefficientList[InverseSeries[Series[y - y^2 - y^4 - y^5, {y, 0, 30}], x], x]
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PROG
| (Maxima)
a(n):=sum((sum(binomial(j, n-k-2*j-1)*binomial(k, j), j, floor((n-k-1)/3), floor((n-k-1)/2)))*binomial(n+k-1, n-1), k, 0, n-1)/n; [From Vladimir Kruchinin kru(AT)ie.tusur.ru, May 26 2011]
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CROSSREFS
| Sequence in context: A151287 A101265 A101879 * A150188 A150189 A144169
Adjacent sequences: A063020 A063021 A063022 * A063024 A063025 A063026
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KEYWORD
| nonn,easy
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AUTHOR
| Olivier Gerard (olivier.gerard(AT)gmail.com), Jul 05 2001.
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