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A094624 Expansion of x*(1+11*x+x^2)/((1-x)*(1+x)*(1-10*x^2)). 4

%I

%S 0,1,11,12,121,122,1221,1222,12221,12222,122221,122222,1222221,

%T 1222222,12222221,12222222,122222221,122222222,1222222221,1222222222,

%U 12222222221,12222222222,122222222221,122222222222,1222222222221,1222222222222,12222222222221

%N Expansion of x*(1+11*x+x^2)/((1-x)*(1+x)*(1-10*x^2)).

%C Previous name: "Sequence whose n-th term digits sum to n."

%C n-th term digits are reversals of A094623(n).

%H Colin Barker, <a href="/A094624/b094624.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (0,11,0,-10).

%F a(n) = 10^(n/2)*(11/18 + 11*sqrt(10)/180 - (11*sqrt(10)/180 - 11/18)(-1)^n) - 13/18 - (-1)^n/2.

%F From _Colin Barker_, Dec 01 2015: (Start)

%F a(n) = 11*a(n-2) - 10*a(n-4) for n > 3.

%F G.f.: x*(1+11*x+x^2) / ((1-x)*(1+x)*(1-10*x^2)). (End)

%o (PARI) concat(0, Vec(x*(1+11*x+x^2)/((1-x)*(1+x)*(1-10*x^2)) + O(x^40))) \\ _Colin Barker_, Dec 01 2015

%Y Cf. A094625, A094626.

%K nonn,base,easy

%O 0,3

%A _Paul Barry_, May 15 2004

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Last modified November 13 20:57 EST 2019. Contains 329106 sequences. (Running on oeis4.)