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A137448 A triangular sequence based on concepts of operations on existing sequences: in this case the T(x,n) ( A053120 ) traditional Chebyshev of the first kind is differentiated twice : p(x,n)=-x^2*T''(x,n)+T(x,n). +0
1
1, 1, 1, -1, 0, -2, 0, -3, 0, -20, 1, 0, 8, 0, -88, 0, 5, 0, 100, 0, -304, -1, 0, -18, 0, 528, 0, -928, 0, -7, 0, -280, 0, 2128, 0, -2624, 1, 0, 32, 0, -1760, 0, 7424, 0, -7040, 0, 9, 0, 600, 0, -8208, 0, 23616, 0, -18176, -1, 0, -50, 0, 4400, 0, -32480, 0, 70400, 0, -45568 (list; table; graph; listen)
OFFSET

1,6

COMMENT

Row sums are:

{1, 2, -3, -23, -79, -199, -419, -783, -1343, -2159, -3299};

As an operator algebra like an Energy Hamiltonian:

e(n)*T(x,n)=p(x,n)/x^2

Solving at the Chebyshev border of x=1 gives the row sums:

Table[e /. Solve[e*ChebyshevT[n, x] - p[x, n] == 0, e], {n, 0, 10}] /. x -> 1

FORMULA

p(x,n)=-x^2*T''(x,n)+T(x,n)

EXAMPLE

{1},

{1, 1},

{-1, 0, -2},

{0, -3, 0, -20},

{1, 0, 8, 0, -88},

{0, 5, 0, 100, 0, -304},

{-1, 0, -18, 0, 528, 0, -928},

{0, -7, 0, -280, 0, 2128, 0, -2624},

{1, 0, 32, 0, -1760, 0, 7424, 0, -7040},

{0, 9, 0, 600, 0, -8208,0, 23616, 0, -18176},

{-1, 0, -50, 0, 4400, 0, -32480, 0, 70400, 0, -45568}

MATHEMATICA

Clear[p, x, a] p[x, 0] = 1; p[x, 1] = x + 1; p[x_, n_] := p[x, n] = -x^2*D[ChebyshevT[n, x], {x, 2}] + ChebyshevT[n, x]; Table[Expand[p[x, n]], {n, 0, 10}]; a = Table[CoefficientList[p[x, n], x], {n, 0, 10}]; Flatten[a]

CROSSREFS

Sequence in context: A067165 A079981 A117776 this_sequence A035165 A079133 A143143

Adjacent sequences: A137445 A137446 A137447 this_sequence A137449 A137450 A137451

KEYWORD

tabl,uned,sign

AUTHOR

Roger L. Bagula and Gary Adamson (rlbagulatftn(AT)yahoo.com), Apr 18 2008

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Last modified December 3 01:16 EST 2008. Contains 151161 sequences.


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