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Period 5: repeat [1, 2, 2, -1, 1].
1

%I #18 Oct 13 2022 14:21:22

%S 1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,

%T 2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,2,-1,1,1,2,

%U 2,-1,1,1,2,2,-1,1,1,2,2,-1,1

%N Period 5: repeat [1, 2, 2, -1, 1].

%H <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,1).

%t PadRight[{},120,{1,2,2,-1,1}] (* _Harvey P. Dale_, Dec 30 2016 *)

%o (PARI) a(n)=[1,1,2,2,-1][n%5+1] \\ _Charles R Greathouse IV_, Mar 12 2017

%Y Cf. A040001, A028356, A142150, A000012, A175922.

%K sign,easy,less

%O 1,2

%A _Jaroslav Krizek_, Oct 17 2010

%E Edited by _Joerg Arndt_, Sep 16 2013