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A189053
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Expansion of d/dx log(1/(1-x/sqrt(1-4*x^2))).
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1
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1, 1, 7, 9, 41, 61, 225, 369, 1195, 2101, 6227, 11529, 32059, 61741, 163727, 325089, 831505, 1690981, 4206145, 8717049, 21215481, 44633821, 106782837, 227363409, 536618341, 1153594261, 2693492305, 5835080169, 13507578125, 29443836301
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OFFSET
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0,3
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LINKS
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Vincenzo Librandi, Table of n, a(n) for n = 0..100
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FORMULA
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G.f. sqrt(1-4*x^2)/(16*x^4+sqrt(1-4*x^2)*(4*x^3-x)-8*x^2+1),
a(n)=n*sum(k=1..n, (binomial((n-2)/2,(n-k)/2)*2^(n-k-1)*((-1)^(n-k)+1))/k);
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PROG
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(Maxima) a(n):=n*sum((binomial((n-2)/2, (n-k)/2)*2^(n-k-1)*((-1)^(n-k)+1))/k, k, 1, n);
(Pari) x='x+O('x^66); /* that many terms */
Vec(deriv(log(1/(1-x/sqrt(1-4*x^2))))) /* show terms */ /* Joerg Arndt, Apr 16 2011 */
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CROSSREFS
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Sequence in context: A140787 A032695 A007449 * A067649 A025631 A038275
Adjacent sequences: A189050 A189051 A189052 * A189054 A189055 A189056
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KEYWORD
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nonn
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AUTHOR
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Vladimir Kruchinin, Apr 16 2011
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STATUS
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approved
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