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A366070
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Expansion of (1/x) * Series_Reversion( x*(1+x-x^2)/(1+x)^5 ).
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0
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1, 4, 23, 155, 1143, 8932, 72682, 609348, 5227035, 45659020, 404756300, 3632075109, 32928392154, 301152242600, 2775117150576, 25741623112539, 240162703635495, 2252187478291088, 21217451539791085, 200709823787548845, 1905712342347978340
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = (1/(n+1)) * Sum_{k=0..floor(n/2)} binomial(n+k,k) * binomial(4*n-k+4,n-2*k).
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PROG
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(PARI) a(n) = sum(k=0, n\2, binomial(n+k, k)*binomial(4*n-k+4, n-2*k))/(n+1);
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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