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A157746
Expansion of 1/(x^11 + x^10 + x^6 + x^5 + x^4 + x^2 + 1).
0
1, 0, -1, 0, 0, -1, 0, 2, 1, -1, -1, -1, -1, 0, 2, 4, 2, -4, -6, -2, 0, 2, 10, 11, -4, -17, -14, -4, 7, 22, 30, 11, -31, -57, -35, 15, 56, 80, 64, -32, -152, -160, -28, 136, 240, 228, 29, -312, -521, -324, 208, 691, 784, 358, -523, -1401, -1417, -149, 1631, 2560, 1826, -492, -3366, -4692
OFFSET
0,8
REFERENCES
J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. xxxiii.
FORMULA
G.f.: 1/(x^11 + x^10 + x^6 + x^5 + x^4 + x^2 + 1).
a(n) + a(n-2) + a(n-4) + a(n-5) + a(n-6) + a(n-10) + a(n-11) = 0. - Wesley Ivan Hurt, Dec 29 2023
MATHEMATICA
f[x_] = 1 + x + x^5 + x^6 + x^7 + x^9 + x^11;
g[x] = ExpandAll[x^11*f[1/x]];
a = Table[SeriesCoefficient[ Series[1/g[x], {x, 0, 50}], n], {n, 0, 50}]
CROSSREFS
Sequence in context: A302354 A000164 A330261 * A349082 A281010 A316864
KEYWORD
sign,easy
AUTHOR
Roger L. Bagula, Mar 05 2009
EXTENSIONS
New name, Joerg Arndt, Mar 20 2013
STATUS
approved