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%I #28 Dec 12 2023 08:24:04
%S -1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,
%T 9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,
%U -5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3,7,-5,3,-7,9,-9,5,-1,1,-3
%N Period 10: repeat [-1, 1, -3, 7, -5, 3, -7, 9, -9, 5].
%C It appears that abs(a(n)) = abs(A001469(n+1)) mod 10.
%C It also appears that abs(a(n)) = abs(A228767(n+4)) mod 10. - _Michel Marcus_, Sep 04 2013
%H <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (-1,-1,-1,-1,-1,-1,-1,-1,-1).
%F G.f.: ( -1-3*x^2+4*x^3+2*x^5-5*x^6-5*x^8-x^4+4*x^7 ) / ( (1+x)*(1+x+x^2+x^3+x^4)*(x^4-x^3+x^2-x+1) ). - _R. J. Mathar_, Oct 08 2011
%F a(n) = - Sum_{k=1..9} a(n-k). - _Wesley Ivan Hurt_, May 27 2021
%t PadRight[{},120,{-1,1,-3,7,-5,3,-7,9,-9,5}] (* _Harvey P. Dale_, Mar 03 2023 *)
%Y Cf. A001469, A228767.
%K sign,easy,less
%O 0,3
%A _Paul Curtz_, Aug 11 2008