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Search: id:A008486
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| A008486 |
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Expansion of (1+x+x^2)/(1-x)^2. |
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+0
8
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| 1, 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186
(list; graph; listen)
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OFFSET
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0,2
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COMMENT
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Also the Engel expansion of exp^(1/3); cf. A006784 for the Engel expansion definition - Benoit Cloitre (benoit7848c(AT)orange.fr), Mar 03 2002
Coordination sequence for graphite net.
Coordination sequence for 2-dimensional cyclotomic lattice Z[zeta_3].
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REFERENCES
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J.-G. Eon, Algebraic determination of generating functions for coordination sequences in crystal structures, Acta Cryst. A58 (2002), 47-53.
M. Beck and S. Hosten, Cyclotomic polytopes and growth series of cyclotomic lattices, arXiv math.CO/0508136.
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LINKS
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A. S. Fraenkel, New games related to old and new sequences, INTEGERS, Electronic J. of Combinatorial Number Theory, Vol. 4, Paper G6, 2004. (See Table 5.)
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FORMULA
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a(0) = 1; a(n) = 3n, n >= 1.
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CROSSREFS
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Adjacent sequences: A008483 A008484 A008485 this_sequence A008487 A008488 A008489
Sequence in context: A003252 A008585 A031193 this_sequence A036686 A059563 A085126
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KEYWORD
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nonn
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AUTHOR
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njas
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