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A008033
Coordination sequence T2 for Zeolite Code APC.
1
1, 4, 10, 20, 35, 54, 76, 104, 136, 171, 211, 254, 302, 355, 411, 471, 536, 606, 679, 756, 837, 922, 1013, 1107, 1204, 1307, 1414, 1525, 1640, 1758, 1881, 2009, 2141, 2276, 2416, 2561, 2709, 2862, 3018, 3178, 3344, 3513, 3686, 3864, 4046, 4232, 4422, 4616
OFFSET
0,2
REFERENCES
W. M. Meier, D. H. Olson and Ch. Baerlocher, Atlas of Zeolite Structure Types, 4th Ed., Elsevier, 1996
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
Sequence in context: A362072 A102533 A341133 * A047954 A008144 A289388
KEYWORD
nonn,easy
STATUS
approved