A131522 - OEIS

A131522

Expansions of p(x,n)=(x^n - 1)*(x^(n + 1) - 1) for n >= 1, triangle read by rows.

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

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..118.

Gareth Jones and David Singerman, Belyi Functions, Hypermaps and Galois Groups, Bull. London Math Soc. 28, (1996) pages 561-590 (dihedral group invariant on page 585).

EXAMPLE

{1, -1, -1, 1},

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

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

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

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

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

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

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

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

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

MATHEMATICA

p[n_] = ExpandAll[(x^n - 1)*(x^(n + 1) - 1)];

a = Table[CoefficientList[p[n], x], {n, 1, 10}];

Flatten[a]

CROSSREFS

Sequence in context: A342892 A071036 A071038 * A221641 A144473 A011750

Adjacent sequences: A131519 A131520 A131521 * A131523 A131524 A131525

KEYWORD

tabf,easy,less,sign

AUTHOR

Roger L. Bagula, Aug 24 2007

STATUS

approved