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%I #14 Feb 13 2017 02:48:22
%S 1,5,22,89,357,1430,5721,22885,91542,366169,1464677,5858710,23434841,
%T 93739365,374957462,1499829849,5999319397,23997277590,95989110361,
%U 383956441445,1535825765782,6143303063129,24573212252517,98292849010070
%N Base-4 digits are, in order, the first n terms of the periodic sequence with initial period 1,1,2.
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (4,0,1,-4).
%H <a href="/index/Ar#2-automatic">Index entries for 2-automatic sequences</a>.
%F G.f.: x*(1+x+2*x^2) / ( (x-1)*(4*x-1)*(1+x+x^2) ). - _R. J. Mathar_, Apr 27 2015
%F A007090(a(n)) = A037535(n).
%t Table[FromDigits[PadRight[{},n,{1,1,2}],4],{n,30}] (* or *) LinearRecurrence[ {4,0,1,-4},{1,5,22,89},30] (* _Harvey P. Dale_, Mar 19 2016 *)
%o (PARI) a(n)=([0,1,0,0; 0,0,1,0; 0,0,0,1; -4,1,0,4]^(n-1)*[1;5;22;89])[1,1] \\ _Charles R Greathouse IV_, Feb 13 2017
%K nonn,base,easy
%O 1,2
%A _Clark Kimberling_
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