0,8

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, 0, -1, 0, -1, -1, -1, 0, 0, 0, -1}}

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

g_2(x)=1 + x + x^5 + x^6 + x^7 + x^9 + x^11;

f(x)=1/(g_2(1/x)*x^11)=1 + x^2 + x^4 + x^5 + x^6 + x^10 + x^11;

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

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}]

Sequence in context: A079635 A037909 A000164 this_sequence A037820 A076493 A037910

Adjacent sequences: A157743 A157744 A157745 this_sequence A157747 A157748 A157749

sign,uned

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