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A104531
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Expansion of (1+sqrt(1-4*x))/(5*sqrt(1-4*x)-3).
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1
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1, 4, 24, 148, 920, 5736, 35808, 223668, 1397496, 8732920, 54575888, 341082504, 2131706864, 13322959888, 83267756400, 520420803060, 3252620324280, 20328841669080, 127055130786960, 794094089779800, 4963086293860560, 31019282772508080, 193870492861908480
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OFFSET
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0,2
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COMMENTS
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Apply the Riordan matrix ((1+sqrt(1-4x))/2,(1-sqrt(1-4x))/2) (inverse of (1/(1-x),x(1-x))) to 5^n.
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LINKS
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FORMULA
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a(n) = 0^n + sum{k=0..n, 4^(k+1)*C(2n-1, n-k-1)*2*(k+1)/(n+k+1)}
D-finite with recurrence: 4*n*a(n) = (41*n-24)*a(n-1) - 50*(2*n-3)*a(n-2). - Vaclav Kotesovec, Oct 17 2012
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MATHEMATICA
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CoefficientList[Series[(1+Sqrt[1-4*x])/(5*Sqrt[1-4*x]-3), {x, 0, 20}], x] (* Vaclav Kotesovec, Oct 17 2012 *)
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PROG
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(PARI) x='x+O('x^66); Vec((1+sqrt(1-4*x))/(5*sqrt(1-4*x)-3)) \\ Joerg Arndt, May 13 2013
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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