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A220665 Array of coefficients of powers of x^2 for (S(2*n+1,x)/x)^3, with Chebyshev's S polynomials A049310 2
1, -8, 12, -6, 1, 27, -108, 171, -136, 57, -12, 1, -64, 480, -1488, 2488, -2472, 1524, -588, 138, -18, 1, 125, -1500, 7575, -21200, 36690, -41700, 32211, -17184, 6330, -1580, 255, -24, 1, -216, 3780, -28098, 117323, -308688, 546864, -680474, 611019, -402264, 195444, -69894, 18153, -3328, 408, -30, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

COMMENTS

The row lengths sequence of this array is 3*n+1 = A016777(n).

For the coefficient array of S(n,x)^3 see A219240. The present array is the odd part of the bisection of that one divided by x^3.

The row polynomials in powers of x^2 are (S(2*n+1,x)/x)^3 = sum(a(n,m)*x^(2*m), m=0..3*n), n >= 0. The o.g.f. for these row polynomials is GS3odd(x,z) = ((z+1)^2 +2*z*(x^2-3))/ (((z+1)^2-z*x^2)*((z+1)^2-z*x^2*(x^2-3)^2)). This is obtained from the odd part of the bisection of the o.g.f. for A219240.

LINKS

Table of n, a(n) for n=0..50.

FORMULA

a(n,m) = [x^m](S(2*n+1,x)/x)^3, n>=0, 0 <= m <= 3*n.

a(n,m) = [x^m]([z^n]GS3odd(x,z)) with GS3odd(x,z) the o.g.f. for the row polynomials in powers of x^2, given in a comment above.

EXAMPLE

The array a(n,m) begins:

n\m  0    1     2     3      4     5     6    7    8  9

0:   1

1:  -8   12    -6     1

2:  27 -108   171  -136     57   -12     1

3: -64  480 -1488  2488  -2472  1524  -588  138  -18  1

...

Row n=4: [125 -1500, 7575, -21200, 36690, -41700, 32211, -17184, 6330, -1580, 255, -24, 1],

Row n=5: [-216, 3780, -28098, 117323, -308688, 546864, -680474, 611019, -402264, 195444, -69894, 18153, -3328, 408, -30, 1],

Row n=6: [343, -8232, 84378, -489608, 1809129, -4562292, 8219967, -10918992, 10927077, -8356272, 4923132, -2240256, 784840, -209580, 41853, -6048, 597, -36, 1],

Row n=1: (S(3,x)/x)^3 = -8 + 12*x^2 - 6*x^4 + 1*x^6, with Chebyshev's S polynomial.

CROSSREFS

Cf. A219240, A220666 (even part of the bisection).

Sequence in context: A033198 A072900 A203836 * A166173 A014453 A160862

Adjacent sequences:  A220662 A220663 A220664 * A220666 A220667 A220668

KEYWORD

sign,easy,tabf

AUTHOR

Wolfdieter Lang, Dec 17 2012

STATUS

approved

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Last modified July 9 14:56 EDT 2020. Contains 335543 sequences. (Running on oeis4.)