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%I #26 Feb 16 2024 10:20:23
%S 101,110011,111000111,111100001111,111110000011111,111111000000111111,
%T 111111100000001111111,111111110000000011111111,
%U 111111111000000000111111111,111111111100000000001111111111,111111111110000000000011111111111,111111111111000000000000111111111111
%N Concatenation of n digits 1, n digits 0 and n digits 1.
%C a(n) is also A145641(n) written in base 2. - _Omar E. Pol_, Oct 15 2008
%C a(n) has 3n digits. - _Omar E. Pol_, Nov 12 2008
%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (1111,-112110,1111000,-1000000).
%F G.f.: x*(101000*x^2 - 2200*x + 101) / ((x-1)*(10*x-1)*(100*x-1)*(1000*x-1)). - _Colin Barker_, Sep 16 2013
%e From _Omar E. Pol_, Nov 12 2008: (Start)
%e n Successive digits of a(n)
%e 1 ( 1 0 1 )
%e 2 ( 1 1 0 0 1 1 )
%e 3 ( 1 1 1 0 0 0 1 1 1 )
%e 4 ( 1 1 1 1 0 0 0 0 1 1 1 1 )
%e 5 ( 1 1 1 1 1 0 0 0 0 0 1 1 1 1 1 )
%e (End)
%p a:= n-> parse(cat(1$n,0$n,1$n)):
%p seq(a(n), n=1..14); # _Alois P. Heinz_, Mar 03 2022
%o (PARI) Vec(x*(101000*x^2-2200*x+101)/((x-1)*(10*x-1)*(100*x-1)*(1000*x-1)) + O(x^100)) \\ _Colin Barker_, Sep 16 2013
%Y Cf. A000533, A135577, A138120, A138144, A138145, A138146, A138826, A145641, A147757, A147759.
%K nonn,base,easy
%O 1,1
%A _Omar E. Pol_, Mar 29 2008
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