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A309907 a(n) is the square of the number consisting of one 1 and n 3's: (133...3)^2. 3


%S 1,169,17689,1776889,177768889,17777688889,1777776888889,

%T 177777768888889,17777777688888889,1777777776888888889,

%U 177777777768888888889,17777777777688888888889,1777777777776888888888889,177777777777768888888888889,17777777777777688888888888889

%N a(n) is the square of the number consisting of one 1 and n 3's: (133...3)^2.

%C All terms are zeroless (elements of A052382).

%H Seiichi Manyama, <a href="/A309907/b309907.txt">Table of n, a(n) for n = 0..500</a>

%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (111,-1110,1000).

%F G.f.: -(40*x^2+58*x+1)/((x-1)*(100*x-1)*(10*x-1)).

%F a(n) = A097166(n)^2 = ((4*10^n-1)/3)^2. - _Seiichi Manyama_, Aug 23 2019

%p a:= n-> parse(cat(1, 3$n))^2:

%p seq(a(n), n=0..18);

%o (PARI) {a(n) = ((4*10^n-1)/3)^2} \\ _Seiichi Manyama_, Aug 23 2019

%Y Cf. A052382, A097166, A102807.

%K nonn,base,easy

%O 0,2

%A _Alois P. Heinz_, Aug 21 2019

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Last modified January 22 03:32 EST 2021. Contains 340360 sequences. (Running on oeis4.)