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a(n) = n^2 mod 11.
8

%I #28 Dec 18 2023 14:00:16

%S 0,1,4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,

%T 1,4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,1,

%U 4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,1,4,9,5,3,3,5,9,4,1,0,1

%N a(n) = n^2 mod 11.

%H G. C. Greubel, <a href="/A070434/b070434.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1).

%F From _R. J. Mathar_, Apr 20 2010: (Start)

%F a(n) = a(n-11).

%F G.f.: ( -x*(1+x)*(x^8+3*x^7+6*x^6-x^5+4*x^4-x^3+6*x^2+3*x+1) ) / ( (x-1)*(1+x+x^2+x^3+x^4+x^5+x^6+x^7+x^8+x^9+x^10) ). (End)

%F a(n) = A010880(n^2). - _Michel Marcus_, Mar 24 2016

%t Table[Mod[n^2,11],{n,0,200}] (* _Vladimir Joseph Stephan Orlovsky_, Apr 21 2011 *)

%o (PARI) a(n)=n^2%11 \\ _Charles R Greathouse IV_, Apr 06 2016

%Y Cf. A010880, A070430, A070431, A070432.

%K nonn,easy

%O 0,3

%A _N. J. A. Sloane_, May 12 2002