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Let n = 10x + y where 0 <= y <= 9, x >= 0. Then a(n) = 9x+y.
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%I #18 Sep 08 2022 08:45:09

%S 0,1,2,3,4,5,6,7,8,9,9,10,11,12,13,14,15,16,17,18,18,19,20,21,22,23,

%T 24,25,26,27,27,28,29,30,31,32,33,34,35,36,36,37,38,39,40,41,42,43,44,

%U 45,45,46,47,48,49,50,51,52,53,54,54,55,56,57,58,59,60,61,62,63,63,64,65,66,67,68,69,70,71,72,72,73,74,75,76,77,78,79,80,81,81,82,83,84,85,86,87,88,89,90,90,91,92,93,94,95,96,97,98,99,99,100,101,102,103,104,105,106,107,108,108,109,110

%N Let n = 10x + y where 0 <= y <= 9, x >= 0. Then a(n) = 9x+y.

%C More than the usual number of terms are displayed in order to distinguish this from some closely related sequences. - _N. J. A. Sloane_, Mar 22 2014

%H <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,0,0,0,0,0,1,-1).

%F G.f.: x*(x^2 +x +1)*(x^6 +x^3 +1) / ((x -1)^2*(x +1)*(x^4 -x^3 +x^2 -x +1)*(x^4 +x^3 +x^2 +x +1)). - _Colin Barker_, Jun 24 2014

%F a(n) = n - floor(n/10). - _Bruno Berselli_, Jun 24 2014

%p f1:=proc(n) local x,y;

%p y:= (n mod 10);

%p x:=(n-y)/10;

%p 9*x+y;

%p end;

%p [seq(f1(n),n=0..200)];

%o (PARI) my(n, x, y); vector(500, n, y=(n-1)%10; x=(n-1-y)\10; 9*x+y) \\ _Colin Barker_, Jun 23 2014

%o (PARI) a(n)=n - n\10 \\ _Charles R Greathouse IV_, Sep 01 2015

%o (Magma) k:=9; [n-(10-k)*Floor(n/10): n in [0..150]]; // _Bruno Berselli_, Jun 24 2014

%Y Cf. A081502. Different from A028904.

%K nonn,easy

%O 0,3

%A _N. J. A. Sloane_, Apr 22 2003