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A072153 Coordination sequence for VPl-5 structure with respect to node (Y) where 18-gon, hexagon and square meet. 2
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 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

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.

REFERENCES

M. E. Davis, Ordered porous materials for emerging applications, Nature, 417 (Jun 20 2002), 813-821 (gives structure).

LINKS

Joseph Myers, Table of n, a(n) for n = 0..1000

N. J. A. Sloane, VPl-5 structure, after Davis

FORMULA

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]

CROSSREFS

Cf. A072149-A072154.

Sequence in context: A047584 A229089 A277573 * A206929 A230060 A039025

Adjacent sequences:  A072150 A072151 A072152 * A072154 A072155 A072156

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Jun 28 2002

EXTENSIONS

Extended by Joseph Myers, Sep 30 2011

STATUS

approved

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Last modified January 21 11:54 EST 2019. Contains 319356 sequences. (Running on oeis4.)