A157748 Expansion of 1/(-x^11 + x^10 + 2*x^7 - x^6 - x^5 - x^4 - x^2 + 2*x + 1).

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

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.

Index entries for linear recurrences with constant coefficients, signature (-2, 1, 0, 1, 1, 1, -2, 0, 0, -1, 1).

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: A348619 A101911 A052109 * A046170 A369145 A262320

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