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A028289
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Expansion of (1+x^2+x^3+x^5)/((1-x)(1-x^3)(1-x^4)(1-x^6)).
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3
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1, 1, 2, 4, 5, 7, 11, 13, 17, 23, 27, 33, 42, 48, 57, 69, 78, 90, 106, 118, 134, 154, 170, 190, 215, 235, 260, 290, 315, 345, 381, 411, 447, 489, 525, 567, 616, 658, 707, 763, 812, 868, 932, 988, 1052, 1124, 1188
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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REFERENCES
| B. N. Cyvin et al., Enumeration of conjugated hydrocarbons..., Structural Chem., 6 (1995), 85-88, equations (6) and (22).
W. C. Huffman, The biweight enumerator of self-orthogonal binary codes, Discrete Math., 26 (1979), 129-143.
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,1,1,-2,-2,1,1,1,-1).
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FORMULA
| G.f. 1 / ( (1+x)*(1+x+x^2)^2*(x-1)^4 ). - R. J. Mathar, Mar 22 2011
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MAPLE
| A117373 := proc(n) op(1+(n mod 6), [1, -2, -3, -1, 2, 3]) ; end proc:
A076118 := proc(n) coeftayl( x*(1-x)/(1-x+x^2)^2, x=0, n) ; end proc:
A028289 := proc(n) 1/108*n^3 +1/8*n^2 +55/108*n +29/48 +1/16*(-1)^n -2*(-1)^n*A117373(n+2)/27 +(-1)^n*A076118(n+1)/9; end proc:
seq(A028289(n), n=0..20) ; # R. J. Mathar, Mar 22 2011
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MATHEMATICA
| CoefficientList[Series[(1+x^2+x^3+x^5)/((1-x)(1-x^3)(1-x^4) (1-x^6)), {x, 0, 50}], x] (* From Harvey P. Dale, Apr 20 2011 *)
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CROSSREFS
| Sequence in context: A033160 A110924 A192590 * A039673 A097581 A090614
Adjacent sequences: A028286 A028287 A028288 * A028290 A028291 A028292
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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