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A157748 Expansion of 1/(-x^11 + x^10 + 2*x^7 - x^6 - x^5 - x^4 - x^2 + 2*x + 1). 0
1, -2, 5, -12, 30, -73, 180, -444, 1095, -2699, 6653, -16399, 40421, -99632, 245580, -605324, 1492048, -3677712, 9065100, -22344336, 55075988, -135755408, 334620068, -824796535, 2033020102, -5011139791, 12351831632, -30445717146 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

REFERENCES

J. H. Conway and N. J. A. Sloane, "Sphere Packings, Lattices and Groups", Springer-Verlag, p. xxxiii.

LINKS

Table of n, a(n) for n=0..27.

FORMULA

G.f.: 1/(-x^11 + x^10 + 2*x^7 - x^6 - x^5 - x^4 - x^2 + 2*x + 1).

MATHEMATICA

f[x_] = -1 + x + 2*x^4 - x^5 - x^6 - x^7 - x^9 + 2*x^10 + 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: A291253 A101911 A052109 * A046170 A262320 A062423

Adjacent sequences:  A157745 A157746 A157747 * A157749 A157750 A157751

KEYWORD

sign,easy

AUTHOR

Roger L. Bagula, Mar 05 2009

EXTENSIONS

New name from Joerg Arndt, Mar 20 2013

STATUS

approved

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Last modified August 12 23:19 EDT 2020. Contains 336440 sequences. (Running on oeis4.)