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A126271 a(n) = order of Galois group of the polynomial P(x) + n if P(x) + n (after dividing by the gcd of its coefficients) is irreducible, otherwise a(n) = 0, where P(x) = 128*x^8 - 256*x^6 + 160*x^4 - 32*x^2 + 1. 1
32, 32, 16, 32, 32, 32, 32, 32, 32, 16, 32, 32, 32, 16, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 32, 16, 16, 32, 32, 32 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

P(x) = T_8(x) is the degree 8 Chebyshev polynomial of the first kind.

LINKS

Table of n, a(n) for n=0..30.

Eric Weisstein's World of Mathematics, Chebyshev Polynomial of the First Kind

PROG

(MAGMA) Q:=RationalField(); R<x>:=PolynomialRing(Q); f:=128*x^8 - 256*x^6 + 160*x^4 - 32*x^2 + 0; for n in {0 .. 30} do f:=f+1; Order(GaloisGroup(f)); end for; /* N. J. A. Sloane */

CROSSREFS

Cf. A124827, A126270.

Sequence in context: A022988 A023474 A208129 * A010871 A022366 A165853

Adjacent sequences:  A126268 A126269 A126270 * A126272 A126273 A126274

KEYWORD

nonn

AUTHOR

Artur Jasinski, Dec 23 2006

EXTENSIONS

Edited by N. J. A. Sloane, Dec 28 2007

STATUS

approved

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Last modified June 19 01:38 EDT 2013. Contains 226359 sequences.