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Search: id:A053123
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| A053123 |
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Triangle of coefficients of shifted Chebyshev's S(n,x-2)= U(n,x/2-1) polynomials (exponents of x in decreasing order). |
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+0 13
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| 1, 1, -2, 1, -4, 3, 1, -6, 10, -4, 1, -8, 21, -20, 5, 1, -10, 36, -56, 35, -6, 1, -12, 55, -120, 126, -56, 7, 1, -14, 78, -220, 330, -252, 84, -8, 1, -16, 105, -364, 715, -792, 462, -120, 9, 1, -18, 136, -560, 1365, -2002, 1716, -792, 165, -10, 1, -20, 171, -816, 2380, -4368, 5005, -3432, 1287, -220, 11, 1
(list; table; graph; listen)
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OFFSET
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0,3
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COMMENT
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a(n,m)= A053122(n,n-m).
G.f. for row polynomials and row sums same as in A053122.
Unsigned column sequences are A000012, A005843, A014105, A002492 for m=0..3, resp. and A053126-A053131 for m=4..9.
This is also the coeficient triangle for Chebyshev's U(2*n+1,x) polynomials expanded in decreasing odd powers of (2*x): U(2*n+1,x)=sum(a(n,m)*(2*x)^(2*(n-m)+1), m=0..n). See the W. Lang link given in A053125.
Unsigned version is mirror image of A078812 . [From Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Dec 02 2008]
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REFERENCES
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M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, 1964 (and various reprintings), p. 795
Theodore J. Rivlin, Chebyshev polynomials: from approximation theory to algebra and number theory, 2. ed., Wiley, New York, 1990.
Stephen Barnett, "Matrices: Methods and Applications", Oxford University Press, 1990, p. 132, 343.
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LINKS
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T. D. Noe, Rows n=0..50 of triangle, flattened
M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards, Applied Math. Series 55, Tenth Printing, 1972 [alternative scanned copy].
Index entries for sequences related to Chebyshev polynomials.
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FORMULA
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a(n, m) := 0 if n<m else ((-1)^m)*binomial(2*n+1-m, m);
a(n, m) := -2*a(n-1, m-1)+a(n-1, m)-a(n-2, m-2), a(n, -2) := 0 =: a(-2, m), a(n, -1) := 0 =: a(-1, m), a(0, 0)=1, a(n, m)= 0 if n<m;
G.f. for m-th column (signed triangle): ((-1)^m)*x^m*Po(m+1, x)/(1-x)^(m+1), with Po(k, x) := sum('binomial(k, 2*j+1)*x^j', 'j'=0..floor(k/2)).
The n-th degree polynomial is the characteristic equation for an n X n tridiagonal matrix with (diagonal = all 2's, sub and superdiagonals all -1's and the rest 0's), exemplified by the 4X4 matrix M = [2 -1 0 0 / -1 2 -1 0 / 0 -1 2 -1 / 0 0 -1 2]. - Gary W. Adamson (qntmpkt(AT)yahoo.com), Jan 05 2005
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EXAMPLE
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{1}; {1,-2}; {1,-4,3}; {1,-6,10,-4}; {1,-8,21,-20,5};... E.g. fourth row (n=3) {1,-6,10,-4} corresponds to polynomial S(3,x-2)= x^3-6*x^2+10*x-4.
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CROSSREFS
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Cf. A053124, A053122.
Sequence in context: A093190 A132191 A094437 this_sequence A107661 A126570 A048790
Adjacent sequences: A053120 A053121 A053122 this_sequence A053124 A053125 A053126
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KEYWORD
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easy,sign,tabl
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang(AT)physik.uni-karlsruhe.de)
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