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A270369 Expansion of (1-7*x)/(1-9*x). 2


%S 1,2,18,162,1458,13122,118098,1062882,9565938,86093442,774840978,

%T 6973568802,62762119218,564859072962,5083731656658,45753584909922,

%U 411782264189298,3706040377703682,33354363399333138,300189270593998242,2701703435345984178

%N Expansion of (1-7*x)/(1-9*x).

%H Colin Barker, <a href="/A270369/b270369.txt">Table of n, a(n) for n = 0..1000</a>

%H <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (9).

%F G.f.: (1-7*x)/(1-9*x).

%F a(n) = 9*a(n-1) for n>1.

%F a(n) = 2*9^(n-1) for n>0.

%t CoefficientList[Series[(1-7x)/(1-9x),{x,0,20}],x] (* or *) Join[ {1}, NestList[9#&,2,20]] (* _Harvey P. Dale_, Oct 15 2017 *)

%o (PARI) Vec((1-7*x)/(1-9*x) + O(x^30))

%Y Cf. A001019 (powers of 9), A054879 (partial sums).

%Y Cf. similar sequences with g.f. (1-k*x)/(1-9*x) and k=0..8: A001019 (k=0; k=8 gives two initial 1's ), A055275 (k=1), A270472 (k=2), A092810 (k=3), A067403 (k=4), A270473 (k=5), A102518 (k=6), this sequence (k=7).

%K nonn,easy

%O 0,2

%A _Colin Barker_, Mar 18 2016

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Last modified September 29 10:54 EDT 2020. Contains 337428 sequences. (Running on oeis4.)