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A092807
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Expansion of (1-6x+4x^2)/((1-2x)(1-6x)).
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0
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1, 2, 8, 40, 224, 1312, 7808, 46720, 280064, 1679872, 10078208, 60467200, 362799104, 2176786432, 13060702208, 78364180480, 470185017344, 2821109972992, 16926659575808, 101559956930560, 609359740534784
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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COMMENTS
| Second binomial transform of A054881 (closed walks at a vertex of an octahedron) With interpolated zeros, counts closed walks of length n at a vertex of the edge-vertex incidence graph of K_4 associated with the edges of K_4.
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FORMULA
| a(n)=6^n/6+2^n/2+0^n/3
a(n)=A074601(n-1), n>0. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Sep 08 2008]
a(0)=1, a(1)=2, a(2)=8, a(n)=8*a(n-1)-12*a(n-2) [From Harvey P. Dale, Aug 23 2011]
a(n)=A124302(n)*2^n. - From DELEHAM Philippe, Nov 01 2011
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MATHEMATICA
| CoefficientList[Series[(1-6x+4x^2)/((1-2x)(1-6x)), {x, 0, 40}], x] (* or *) Join[{1}, LinearRecurrence[{8, -12}, {2, 8}, 40]] (* From Harvey P. Dale, Aug 23 2011 *)
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CROSSREFS
| Cf. A092803.
Sequence in context: A143388 A027282 A006195 * A074601 A052701 A151374
Adjacent sequences: A092804 A092805 A092806 * A092808 A092809 A092810
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KEYWORD
| easy,nonn
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AUTHOR
| Paul Barry (pbarry(AT)wit.ie), Mar 06 2004
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