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A122188 Triangle read by rows, formed from the coefficients of characteristic polynomials of the following sequence of matrices: 2 X 2 {{0, 1}, {1, 1}}, 3 X 3 {{0, 1, 0}, {0, 0, 1}, {1, 1, 1}}, 4 X 4 {{0, 1,0, 0}, {0, 0, 1, 0}, {0, 0, 0, 1}, {1, 1, 1, 1}}, 5 X 5 {{0, 1, 0, 0, 0}, {0, 0, 1, 0, 0}, {0, 0, 0, 1, 0}, {0, 0, 0, 0, 1}, {1, 1, 1, 1, 1}}, ... +0
3
1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1 (list; table; graph; listen)
OFFSET

1,1

COMMENT

Row sums are: {1, 0, -1, 2, -3, 4, -5, 6, -7, 8, -9}

FORMULA

B(x, n) = If[n > 1, (-1)^n*(x^n - Sum[x^m, {m, 0, n - 1}])]

EXAMPLE

Triangular array:

{1},

{1, -1},

{-1, -1, 1},

{1, 1, 1, -1},

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

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

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

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

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

MATHEMATICA

An[d_] := Table[If[n == d, 1, If[m == n + 1, 1, 0]], {n, 1, d}, {m, 1, d}]; Join[{{1}}, Table[CoefficientList[CharacteristicPolynomial[An[d], x], x], {d, 1, 20}]]; Flatten[%]

Clear[B, x, n] B[x, 0] = 1; B[x, 1] = -x + 1; B[x_, n_] := B[x, n] = If[n > 1, (-1)^n*(x^n - Sum[x^m, {m, 0, n - 1}])]; Table[ExpandAll[B[x, n]], {n, 0, 10}]; a = Table[CoefficientList[B[x, n], x], {n, 0, 10}]; Flatten[a] Table[Apply[Plus, CoefficientList[B[x, n], x]], {n, 0, 10}]

CROSSREFS

Cf. A000073, A000045.

Sequence in context: A106400 A112865 A121241 this_sequence A130151 A131561 A065357

Adjacent sequences: A122185 A122186 A122187 this_sequence A122189 A122190 A122191

KEYWORD

tabl,sign

AUTHOR

Gary Adamson and Roger Bagula (qntmpkt(AT)yahoo.com), Oct 18 2006, Mar 18 2008

EXTENSIONS

Edited by njas, Apr 14 2008

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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