%I #20 Jan 03 2024 08:50:22
%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,
%T -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,
%U 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
%N a(0)=a(1)=1, a(n) = -a(n-1) for n > 1.
%C Inverse binomial transform of A040000(n) = 1,2,2,2,2,...; binomial transform of (-1)^(n+1)*A000918(n) = 1,0,-2,6,-14,30,-62,... - _Philippe Deléham_, Sep 16 2009
%C This is also the Z-sequence of the Riordan triangle A105809. See the W. Lang link under A006232 for Riordan A- and Z-sequences. - _Wolfdieter Lang_, Oct 04 2014
%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (-1).
%F G.f.: (1+2*x)/(1+x).
%F E.g.f.: 2-exp(-x).
%F a(n) = -a(n-1). - _Wesley Ivan Hurt_, Apr 23 2021
%t PadRight[{1},120,{-1,1}] (* _Harvey P. Dale_, Dec 04 2012 *)
%t Join[{1},LinearRecurrence[{-1},{1},83]] (* _Ray Chandler_, Aug 12 2015 *)
%Y Cf. A033999.
%K easy,sign,mult
%O 0,1
%A _Philippe Deléham_, Sep 14 2009