OFFSET
0,2
REFERENCES
Inorganic Crystal Structure Database: Collection Code 67669.
LINKS
Sean A. Irvine, Table of n, a(n) for n = 0..1000
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
a(3*m) = 22*m^2+2, a(3*m+1) = 22*m^2+14*m+4, a(3*m+2) = 22*m^2+30*m+12, m>0. - N. J. A. Sloane
G.f.: (1+3*x+6*x^2+12*x^3+10*x^4+12*x^5-x^6+x^7-2*x^8+2*x^9) / ((1-x)^3*(1+x+x^2)^2). - Colin Barker, Dec 23 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved