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A072153
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Coordination sequence for VPl-5 structure with respect to node (Y) where 18-gon, hexagon and square meet.
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2
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1, 3, 5, 6, 7, 9, 11, 13, 16, 19, 20, 20, 22, 25, 27, 29, 32, 34, 34, 35, 38, 41, 43, 45, 47, 48, 49, 51, 54, 57, 59, 60, 61, 63, 65, 67, 70, 73, 74, 74, 76, 79, 81, 83, 86, 88, 88, 89, 92, 95, 97, 99, 101, 102, 103, 105, 108, 111, 113, 114, 115, 117, 119, 121, 124
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OFFSET
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0,2
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COMMENTS
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There are two types of nodes in this structure.
The coordination sequence with respect to a particular node gives the number of nodes that can be reached from that node in n steps along edges.
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REFERENCES
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M. E. Davis, Ordered porous materials for emerging applications, Nature, 417 (Jun 20 2002), 813-821 (gives structure).
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LINKS
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FORMULA
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Empirical G.f.: (x^2+x+1)^2*(x^6+x^3+1)/((x-1)^2*(x^2+1)*(x^6+x^5+x^4+x^3+x^2+x+1)). [Colin Barker, Nov 18 2012]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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