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A072149 Coordination sequence for AlPO_4-11 structure with respect to node (X) where decagon and two hexagons meet. 6
1, 3, 6, 8, 10, 13, 16, 19, 20, 22, 28, 31, 30, 33, 38, 40, 42, 43, 46, 53, 54, 52, 58, 63, 62, 65, 68, 70, 76, 77, 76, 83, 86, 84, 90, 93, 92, 99, 102, 100, 106, 109, 108, 115, 116, 114, 124, 127, 122, 129, 134, 132, 138, 139, 138, 149, 150, 144, 154, 159 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
There are three 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.
LINKS
M. E. Davis, Ordered porous materials for emerging applications, Nature, 417 (Jun 20 2002), 813-821 (gives structure).
R. J. Mathar, Illustration of counts and adjacencies (PostScript)
FORMULA
Empirical: G.f. 1 +x*(3 +6*x +11*x^2 +13*x^3 +15*x^4 +15*x^5 +16*x^6 +15*x^7 +15*x^8 +13*x^9 +11*x^10 +6*x^11 +3*x^12) / ( (1+x^2)*(x^6+x^3+1)*(x-1)^2*(1+x+x^2)^2 ) with a(n)= -a(n-2) +a(n-3) +a(n-5) +a(n-9) +a(n-11) -a(n-12) -a(n-14). - R. J. Mathar, Sep 30 2011
CROSSREFS
Sequence in context: A190325 A064437 A287180 * A001066 A099518 A280106
KEYWORD
nonn,easy
AUTHOR
N. J. A. Sloane, Jun 28 2002
EXTENSIONS
More terms from R. J. Mathar, Mar 29 2007
Extended by Joseph Myers, Sep 29 2011
STATUS
approved

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Last modified March 19 06:05 EDT 2024. Contains 370952 sequences. (Running on oeis4.)