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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 Joseph Myers, Table of n, a(n) for n = 0..1000 M. E. Davis, Ordered porous materials for emerging applications, Nature, 417 (Jun 20 2002), 813-821 (gives structure). N. J. A. Sloane, AlPO_4-11 structure, after Davis 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 Cf. A072150-A072154. Sequence in context: A190325 A064437 A287180 * A001066 A099518 A280106 Adjacent sequences:  A072146 A072147 A072148 * A072150 A072151 A072152 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 December 6 21:45 EST 2019. Contains 329809 sequences. (Running on oeis4.)