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A092803
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Expansion of (1-5x)/((1-2x)(1-6x)).
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1
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1, 3, 12, 60, 336, 1968, 11712, 70080, 420096, 2519808, 15117312, 90700800, 544198656, 3265179648, 19591053312, 117546270720, 705277526016, 4231664959488, 25389989363712, 152339935395840, 914039610802176
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OFFSET
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0,2
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COMMENTS
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Second binomial transform of expansion of (1-3x)/(1-4x). Third binomial transform of A054878 (closed walks at a vertex of K_4). With interpolated zeros, counts closed walks of length n at the vertices of the edge-vertex incidence graph of K_4 associated with the vertices of K_4.
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LINKS
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Table of n, a(n) for n=0..20.
Index entries for linear recurrences with constant coefficients, signature (8,-12).
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FORMULA
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a(n)=2^(n-2)(3^n+3)=(6^n+3*2^n)/4
G.f.: U(0)/4 where U(k)= 1 + 2/(3^k - 3^k/(2 + 1 - 12*x*3^k/(6*x*3^k + 1/U(k+1)))) ; (continued fraction, 4-step). - Sergei N. Gladkovskii, Oct 30 2012
G.f.: U(0)/4 where U(k)= 1 + 3/( 3^k - 2*x*9^k/(2*x*3^k + 1/U(k+1))) ; (continued fraction, 3-step). - Sergei N. Gladkovskii, Oct 31 2012
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CROSSREFS
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Sequence in context: A003483 A278395 A128602 * A181282 A020052 A096471
Adjacent sequences: A092800 A092801 A092802 * A092804 A092805 A092806
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KEYWORD
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easy,nonn
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AUTHOR
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Paul Barry, Mar 06 2004
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STATUS
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approved
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