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%I #11 Sep 22 2017 19:43:01
%S 4,50,450,4590,45405,454950,4544550,45454500,454495500,4545045000,
%T 45449955000,454500450000,4544999550000,45450004500000,
%U 454499995500000,4545000045000000,45449999955000000,454500000450000000,4544999999550000000,45450000004500000000
%N Number of numbers that yield an n-digit number after Reverse and Add!.
%C A190481 is the number of distinct n-digit numbers after Reverse and Add!.
%H Colin Barker, <a href="/A232731/b232731.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (10,10,-100).
%F a(1) = A232729(1), a(n) = A232729(n) + A232730(n-1), n > 1.
%F From _Colin Barker_, Mar 20 2017: (Start)
%F G.f.: x*(4 + 10*x - 90*x^2 - 10*x^3 + 5*x^4) / ((1 - 10*x)*(1 - 10*x^2)).
%F a(n) = 10*a(n-1) + 10*a(n-2) - 100*a(n-3) for n>5.
%F (End)
%t LinearRecurrence[{10,10,-100},{4,50,450,4590,45405},20] (* _Harvey P. Dale_, Sep 22 2017 *)
%o (PARI) Vec(x*(4 + 10*x - 90*x^2 - 10*x^3 + 5*x^4) / ((1 - 10*x)*(1 - 10*x^2)) + O(x^30)) \\ _Colin Barker_, Mar 20 2017
%Y Cf. A190481, A232729, A232730.
%K nonn,easy
%O 1,1
%A _Lars Blomberg_, Nov 29 2013
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