OFFSET
0,2
REFERENCES
W. M. Meier, D. H. Olson and Ch. Baerlocher, Atlas of Zeolite Structure Types, 4th Ed., Elsevier, 1996
LINKS
R. W. Grosse-Kunstleve, Table of n, a(n) for n = 0..1000
R. W. Grosse-Kunstleve, Coordination Sequences and Encyclopedia of Integer Sequences
R. W. Grosse-Kunstleve, G. O. Brunner, and N. J. A. Sloane, Algebraic Description of Coordination Sequences and Exact Topological Densities for Zeolites, Acta Cryst., A52 (1996), pp. 879-889.
Sean A. Irvine, Generating Functions for Coordination Sequences of Zeolites, after Grosse-Kunstleve, Brunner, and Sloane
International Zeolite Association, Database of Zeolite Structures
FORMULA
G.f.: (1 + x)*(1 + 2*x + 4*x^2 + 6*x^3 + 9*x^4 + 9*x^5 + 10*x^6 + 12*x^7 + 10*x^8 + 9*x^9 + 9*x^10 + 6*x^11 + 4*x^12 + 2*x^13 + x^14) / ((1 - x)^3*(1 + x + x^2)*(1 + x + x^2 + x^3 + x^4)*(1 + x^3 + x^6)). - Colin Barker, Dec 20 2015
G.f.: (1 + 3*x + 6*x^2 + 10*x^3 + 15*x^4 + 18*x^5 + 19*x^6 + 22*x^7 + 22*x^8 + 19*x^9 + 18*x^10 + 15*x^11 + 10*x^12 + 6*x^13 + 3*x^14 + x^15) / (1 - x) / (1 - x^5) / (1 - x^9). - Sean A. Irvine, Mar 13 2018
a(n) ~ 94*n^2/45. - Stefano Spezia, Dec 17 2022
MATHEMATICA
CoefficientList[Series[(1 + 3*x + 6*x^2 + 10*x^3 + 15*x^4 + 18*x^5 + 19*x^6 + 22*x^7 + 22*x^8 + 19*x^9 + 18*x^10 + 15*x^11 + 10*x^12 + 6*x^13 + 3*x^14 + x^15)/(1-x)/(1-x^5)/(1-x^9), {x, 0, 47}], x] (* Stefano Spezia, Dec 17 2022 *)
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved