0,2

Characteristic matrix of of the toral inverse polynomial is:

{{0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0},

{0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},

{0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0},

{0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0},

{0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0},

{0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0},

{0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0},

{0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0},

{0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0},

{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1},

{1, 2, -1, 0, -1, -1, -1, 2, 0, 0, 1}}

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

g_4(x)=-1 + x + 2*x^4 - x^5 - x^6 - x^7 - x^9 + 2*x^10 + x^11;

f(x)=1/(g_4(1/x)*x^11)=1 + 2 x - x^2 - x^4 - x^5 - x^6 + 2 x^7 + x^10 - x^11;

a(n)=coefficients(f(x))

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}]

Sequence in context: A042789 A101911 A052109 this_sequence A046170 A062423 A118649

Adjacent sequences: A157745 A157746 A157747 this_sequence A157749 A157750 A157751

sign,uned

Roger L. Bagula (rlbagulatftn(AT)yahoo.com), Mar 05 2009