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A098655
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Trace sequence of 3 X 3 symmetric Krawtchouk matrix.
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2
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3, 2, 20, 8, 144, 32, 1088, 128, 8448, 512, 66560, 2048, 528384, 8192, 4210688, 32768, 33619968, 131072, 268697600, 524288, 2148532224, 2097152, 17184063488, 8388608, 137455730688, 33554432, 1099578736640, 134217728, 8796361457664
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OFFSET
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0,1
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COMMENTS
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Let A=[1,2,1;2,0,-2;1,-2,1] the 3 X 3 symmetric Krawtchouk matrix. Then a(n) = trace(A^n).
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LINKS
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FORMULA
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G.f.: (3 - 4*x - 8*x^2)/((1-2*x)*(1-8*x^2)).
a(n) = 2^n + (2*sqrt(2))^n + (-2*sqrt(2))^n.
a(n) = 2*a(n-1) + 8*a(n-2) - 16*a(n-3).
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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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