A033128 - OEIS

A033128

Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,0,1.

%I #19 Dec 14 2023 05:44:38

%S 1,10,101,1011,10110,101101,1011011,10110110,101101101,1011011011,

%T 10110110110,101101101101,1011011011011,10110110110110,

%U 101101101101101,1011011011011011,10110110110110110,101101101101101101,1011011011011011011,10110110110110110110

%N Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,0,1.

%F a(n) = 10*a(n-1) +a(n-3) -10*a(n-4). G.f.: x*(1+x^2)/((x-1) * (10*x-1) * (1+x+x^2)). - _R. J. Mathar_, Oct 05 2009

%F a(n) = floor((101/999)*10^n). - _Tani Akinari_, Jul 22 2015

%t nn=20;With[{c=PadRight[{},nn,{1,0,1}]},Table[FromDigits[ Take[ c,n]],{n,nn}]] (* _Harvey P. Dale_, Dec 30 2012 *)

%K nonn,base

%O 1,2

%A _Clark Kimberling_

%E More terms from _Harvey P. Dale_, Dec 30 2012