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A257593 Number of zeros of the polynomial Sum_{j=0..n-1} z^(2^j-1)outside the unit circle. 1
2, 4, 10, 18, 46, 100, 204, 420, 840, 1708, 3478, 7066, 14286, 28772 (list; graph; refs; listen; history; text; internal format)
OFFSET

3,1

LINKS

Table of n, a(n) for n=3..16.

Karl Dilcher and Larry Ericksen, The Polynomials of Mahler and Roots of Unity, The American Mathematical Monthly, Vol. 122, No. 04 (April 2015), pp. 338-353.

MATHEMATICA

Table[Length[Select[Flatten[Abs[z/.NSolve[Sum[z^(2^j-1), {j, 0, n-1}]==0]]], #>1&]], {n, 3, 13}] (* Vincenzo Librandi, Sep 30 2017 *)

CROSSREFS

Cf. A257592.

Sequence in context: A104723 A206140 A079162 * A197926 A228705 A253772

Adjacent sequences:  A257590 A257591 A257592 * A257594 A257595 A257596

KEYWORD

nonn,more

AUTHOR

N. J. A. Sloane, May 15 2015

STATUS

approved

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Last modified November 20 12:37 EST 2018. Contains 317402 sequences. (Running on oeis4.)