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A008000
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Coordination sequence T1 for Zeolite Code ABW and ATN.
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0
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1, 4, 10, 21, 36, 54, 78, 106, 136, 173, 214, 256, 306, 360, 414, 477, 544, 610, 686, 766, 844, 933, 1026, 1116, 1218, 1324, 1426, 1541, 1660, 1774, 1902, 2034, 2160, 2301, 2446, 2584, 2738, 2896, 3046, 3213, 3384, 3546, 3726, 3910, 4084, 4277, 4474, 4660
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,2
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REFERENCES
| W. M. Meier, D. H. Olson and Ch. Baerlocher, Atlas of Zeolite Structure Types, 4th Ed., Elsevier, 1996
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LINKS
| 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.
International Zeolite Association, Database of Zeolite Structures
Index to sequences with linear recurrences with constant coefficients, signature (1,0,2,-2,0,-1,1).
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FORMULA
| a(3m)=19m^2+2, a(3m+1)=19m^2+13m+4, a(3m+2)=19m^2+25m+10 (N. J. A. Sloane) for m > 0.
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MATHEMATICA
| CoefficientList[Series[(-z^7 - 3 z^6 - 6 z^5 - 9 z^4 - 9 z^3 - 6 z^2 - 3 z - 1)/((z - 1)^3 (z^2 + z + 1)^2), {z, 0, 100}], z] (* From Vladimir Joseph Stephan Orlovsky, Jun 27 2011 *)
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PROG
| (PARI) a(n)=if(n, my(m=divrem(n, 3)); 19*m[1]^2+if(m[2], if(m[2]==1, 13*m[1]+4, 25*m[1]+10), 2), 1) \\ Charles R Greathouse IV, Jun 28 2011
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CROSSREFS
| Sequence in context: A038407 A009894 A027370 * A038408 A038411 A033599
Adjacent sequences: A007997 A007998 A007999 * A008001 A008002 A008003
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KEYWORD
| nonn,easy
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AUTHOR
| R. W. Grosse-Kunstleve (rwgk(AT)cci.lbl.gov)
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