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A084930 Triangle of coefficients of Chebyshev polynomials T_{2n+1} (x). 3
1, -3, 4, 5, -20, 16, -7, 56, -112, 64, 9, -120, 432, -576, 256, -11, 220, -1232, 2816, -2816, 1024, 13, -364, 2912, -9984, 16640, -13312, 4096, -15, 560, -6048, 28800, -70400, 92160, -61440, 16384, 17, -816, 11424, -71808, 239360, -452608, 487424, -278528, 65536, -19, 1140, -20064, 160512, -695552 (list; table; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

Comment from Herb Conn, HCR 83, Box 93, Custer, SD 57730, Jan 28 2005: "Letting x = 2 Cos 2A, we have the following trigonometric identities:

"Sin 3A = 3*Sin A - 4*Sin^3 A

"Sin 5A = 5*Sin A - 20*Sin^3 A + 16*Sin^5 A

"Sin 7A = 7*Sin A - 56*Sin^3 A + 112*Sin^5 A - 64*Sin^7 A

"Sin 9A = 9*Sin A - 120*Sin^3 A + 432*Sin^5 A - 576*Sin^7 A + 256*Sin^9 A, etc."

REFERENCES

Theodore J. Rivlin, Chebyshev polynomials: from approximation theory to algebra and number theory, 2. ed., Wiley, New York, 1990. p. 37, eq.(1.96) and p. 4, eq.(1.10).

LINKS

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].

M. Abramowitz and I. A. Stegun, eds., Handbook of Mathematical Functions, National Bureau of Standards Applied Math. Series 55, Tenth Printing, 1972, p. 795.

Index entries for sequences related to Chebyshev polynomials.

FORMULA

Alternate rows of A008310.

a(n,k)=((-1)^(n-k))*(2^(2*k))*binomial(n+1+k,2*k+1)*(2*n+1)/(n+1+k) if n>=k>=0 else 0.

EXAMPLE

First few polynomials T_{2n+1}(x) are

1*x

4*x^3 - 3*x

16*x^5 - 20*x^3 + 5*x

64*x^7 - 112*x^5 + 56*x^3 - 7*x

256*x^9 - 576*x^7 + 432*x^5 - 120*x^3 + 9*x

CROSSREFS

Cf. A002315, A028297.

Cf. A053120 (coefficient triangle of T-polynomials), A127674 (even indexed T polynomials).

Cf. A127675 (row reversed triangle with different signs).

Sequence in context: A059184 A161961 A161474 * A114336 A048086 A048005

Adjacent sequences:  A084927 A084928 A084929 * A084931 A084932 A084933

KEYWORD

sign,tabl,easy

AUTHOR

Gary W. Adamson (qntmpkt(AT)yahoo.com), Jun 12 2003

EXTENSIONS

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Jun 26 2003

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Last modified February 16 08:13 EST 2012. Contains 205893 sequences.