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A094754 Middle coefficient of cyclotomic polynomial Phi_n(x). 3
0, 0, 1, 0, 1, -1, 1, 0, 1, 1, 1, -1, 1, -1, -1, 0, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 0, -1, 1, 1, -1, 1, -1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, -1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 0, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

a(n) = 0 if n is a power of 2, otherwise a(n) is odd.

LINKS

T. D. Noe, Table of n, a(n) for n=1..10000

G. P. Dresden, On the middle coefficient of a cyclotomic polynomial, Amer. Math. Monthly, 111 (No. 6, 2004), 531-533.

MAPLE

with(numtheory); t1:=[0, 0]; for n from 3 to 120 do t2:=cyclotomic(n, x); t3:=degree(t2, x); t1:=[op(t1), coeff(t2, x, floor(t3/2))]; od: t1;

CROSSREFS

Cf. A095877 (n such that the middle coefficient of Phi_n(x) has a value not obtained for smaller n).

Sequence in context: A143538 A011656 A043545 * A091225 A175337 A132380

Adjacent sequences:  A094751 A094752 A094753 * A094755 A094756 A094757

KEYWORD

sign

AUTHOR

N. J. A. Sloane, Jun 10 2004

STATUS

approved

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Last modified September 24 04:14 EDT 2017. Contains 292402 sequences.