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A257598
Triangle read by rows: coefficients of polynomials W_n(x), highest degree terms first.
0
1, 1, 1, 2, 1, 1, 4, 1, 1, 1, 8, 1, 1, 1, 16, -4, 1, 1, 1, 1, 32, -16, 2, 1, 1, 1, 1, 64, -48, 8, 1, 1, 1, 1, 1, 128, -128, 32, 1, 1, 1, 1, 1, 256, -320, 112, -8, 1, 1, 1, 1, 1, 1, 512, -768, 352, -48, 2, 1, 1, 1, 1, 1, 1
OFFSET
0,4
LINKS
K. Dilcher, K. B. Stolarsky, Nonlinear recurrences related to Chebyshev polynomials, The Ramanujan Journal, 2014, Online Oct. 2014, pp. 1-23.
FORMULA
W(n) = V(n+1)^2 - V(n)*V(n+2) where V(n) are the polynomials defined in A257597. - Michel Marcus, Aug 22 2015
EXAMPLE
Triangle of coefficients begins:
1,
1, 1,
2, 1, 1,
4, 1, 1, 1,
8, 1, 1, 1,
16, -4, 1, 1, 1, 1,
32, -16, 2, 1, 1, 1, 1,
64, -48, 8, 1, 1, 1, 1, 1,
128, -128, 32, 1, 1, 1, 1, 1,
256, -320, 112 -8, 1, 1, 1, 1, 1, 1,
512, -768, 352 -48, 2, 1, 1, 1, 1, 1, 1,
...
The actual polynomials are:
0 1
1 x^2 + 1
2 2x^4 + x^2 + 1
3 4x^6 + x^4 + x^2 + 1
4 8x^8 + x^4 + x^2 + 1
5 16x^10 - 4x^8 + x^6 + x^4 + x^2 + 1
6 32x^12 - 16x^10 + 2x^8 + x^6 + x^4 + x^2 + 1
7 64x^14 - 48x^12 + 8x^10 + x^8 + x^6 + x^4 + x^2 + 1
8 128x^16 - 128x^14 + 32x^12 + x^8 + x^6 + x^4 + x^2 + 1
9 256x^18 - 320x^16 + 112x^14 - 8x^12 + x^10 + x^8 + x^6 + x^4 + x^2 + 1
10 512x^20 - 768x^18 + 352x^16 - 48x^14 + 2x^12 + x^10 + x^8 + x^6 + x^4 + x^2 + 1
...
PROG
(PARI) tabf(nn) = {pp = 1; p = x; for (n=1, nn, np = 2*x*p-pp-x^(n+1); w = p^2 - pp*np; forstep (j=poldegree(w), 0, -1, if (c = polcoeff(w, j), print1(c, ", ")); ); pp = p; p = np; print(); ); } \\ Michel Marcus, Aug 22 2015
CROSSREFS
Cf. A257597.
Sequence in context: A144383 A205553 A178411 * A294580 A294587 A064645
KEYWORD
sign,tabl
AUTHOR
N. J. A. Sloane, Jun 06 2015
EXTENSIONS
One typo in data corrected by Michel Marcus, Aug 22 2015
STATUS
approved