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A089927
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Expansion of 1/((1-x^2)(1-5x+x^2)).
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2
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1, 5, 25, 120, 576, 2760, 13225, 63365, 303601, 1454640, 6969600, 33393360, 159997201, 766592645, 3672966025, 17598237480, 84318221376, 403992869400, 1935646125625, 9274237758725, 44435542668001, 212903475581280
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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LINKS
| Index entries for sequences related to Chebyshev polynomials.
Index to sequences with linear recurrences with constant coefficients, signature (5,0,-5,1)
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FORMULA
| a(n)=5a(n-1)-5a(n-3)+a(n-4).
a(n)=((5-sqrt(21))^n((23-5sqrt(21))/21+(5+sqrt(21))^n((23+5sqrt(21))/21)2^(-1-n)+(-1)^n/14.
a(n)=sum{k=0..floor(n/2), U(n-2k, 5/2)}
a(n) = (-1)^n/14-1/6+(23*A004254(n+1)-5*A004254(n))/21. - R. J. Mathar, Mar 22 2011
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CROSSREFS
| Cf. A003690, A003769.
Sequence in context: A055297 A034274 A110212 * A068539 A123871 A078717
Adjacent sequences: A089924 A089925 A089926 * A089928 A089929 A089930
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Nov 15 2003
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