%I #16 Jul 09 2017 13:54:30
%S 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,
%T 1,1,1,1,1,1,1,1,1,0,0,0,0,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,
%U -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1
%N Inverse of 2021st cyclotomic polynomial.
%C Periodic with period length 2021. - _Ray Chandler_, Apr 07 2017
%H Ray Chandler, <a href="/A016030/b016030.txt">Table of n, a(n) for n = 0..3000</a>
%H <a href="/index/Rec#order_1932">Index entries for linear recurrences with constant coefficients</a>, order 1932.
%H <a href="/index/Pol#poly_cyclo_inv">Index to sequences related to inverse of cyclotomic polynomials</a>
%p with(numtheory,cyclotomic); c := n->series(1/cyclotomic(n,x),x,80);
%t CoefficientList[Series[1/Cyclotomic[2021,x],{x,0,120}],x] (* _Harvey P. Dale_, Jul 09 2017 *)
%K sign
%O 0,1
%A _Simon Plouffe_