OFFSET
0,2
REFERENCES
Gmelin Handbook of Inorg. and Organomet. Chem., 8th Ed., 1994, TYPIX search code (223) cP8.
LINKS
R. W. Grosse-Kunstleve, Table of n, a(n) for n = 0..1000
V. A. Blatov, A. P. Shevchenko, D. M. Proserpio, Applied Topological Analysis of Crystal Structures with the Program Package ToposPro, Cryst. Growth Des. 2014, 14, 3576-3586. See Table I.
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.
FORMULA
G.f.: (1+12*x+51*x^2+130*x^3+243*x^4+350*x^5+450*x^6+418*x^7 +327*x^8+182*x^9+51*x^10+16*x^11-7*x^12+8*x^13+12*x^14)/ ((1+x)*(1+x^2)^2*(1+x+x^2)^2*(1-x)^3). - Robert Israel, Dec 18 2015
Empirical: a(n) = (1903/72) + (3/8)*(-1)^n + 19*KroneckerDelta[n,0] - 8*KroneckerDelta[n,1] - 12*KroneckerDelta[n,2] + ((n+1)/12)*(187*n-273) - (32*sqrt(3)/27)*((13/2)*cos((4n+1)*Pi/6) + sin(2n*Pi/3)) - (3*sqrt(26)/2)*(-1)^n*cos(n*Pi/2 + arctan(1/5)) - (3/4)*i^n*(1+(-1)^n)*(n+2). - G. C. Greubel, Dec 18 2015
G.f.: (1 + 12*x + 50*x^2 + 118*x^3 + 192*x^4 + 220*x^5 + 207*x^6 + 68*x^7-123*x^8-236*x^9-276*x^10-166*x^11-58*x^12-8*x^13 + 19*x^14-8*x^15-12*x^16) / (1-x^3)^2 / (1-x^4)^2. - Sean A. Irvine, Mar 15 2018
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved