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Search: id:A157927
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| A157927 |
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Coefficients of first factor modulo 2 of the P48q lattice polynomial: (x^47+1)=(x+1)*f1(x)*f2(x); f1(x). |
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+0
1
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| 1, 0, 0, 0, -1, -1, 0, 0, 1, 1, 0, -1, -1, -2, 0, 3, 2, 2, 1, -4, -5, -2, 0, 5, 9, 4, -2, -6, -14, -8, 6, 10, 16, 14, -10, -24, -22, -18, 10, 44, 38, 20, -10, -66, -68, -18, 24, 89, 118, 30, -66
(list; graph; listen)
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OFFSET
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0,14
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COMMENT
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J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, pp. 231-232 ( also Chap'7. Example 9)
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FORMULA
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The other one mentioned by Sloane and Conway in "Sphere Packings":
Factor[PolynomialMod[(x^47 + 1)/((x + 1)), 2], Modulus -> 2]
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MATHEMATICA
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f[x_] = 1 + x + x^2 + x^3 + x^5 + x^6 + x^7 + x^9 + x^10 + x^12 + x^13 + x^14 + x^18 + x^19 + x^23;
g[x] = ExpandAll[x^23*f[1/x]];
a = Table[SeriesCoefficient[ Series[1/g[x], {x, 0, 50}], n], {n, 0, 50}]
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CROSSREFS
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Sequence in context: A082785 A100949 A152164 this_sequence A110493 A118234 A152039
Adjacent sequences: A157924 A157925 A157926 this_sequence A157928 A157929 A157930
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KEYWORD
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sign,uned
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AUTHOR
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Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 09 2009
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