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%I #25 Sep 08 2022 08:44:57
%S 0,1,3,4,5,7,8,10,11,12,14,15,17,18,19,21,22,24,25,26,28,29,31,32,33,
%T 35,36,38,39,40,42,43,45,46,47,49,50,52,53,54,56,57,59,60,61,63,64,66,
%U 67,68,70,71,73,74,75,77,78
%N Numbers that are congruent to {0, 1, 3, 4, 5} mod 7.
%H Vincenzo Librandi, <a href="/A047367/b047367.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,1,-1).
%F G.f.: x^2*(1 + 2*x + x^2 + x^3 + 2*x^4) / ( (x^4 + x^3 + x^2 + x + 1)*(x-1)^2 ). - _R. J. Mathar_, Dec 04 2011
%t CoefficientList[Series[x (1 + 2 x + x^2 + x^3 + 2 x^4) / ((x^4 + x^3 + x^2 + x + 1) (x - 1)^2), {x, 0, 60}], x] (* _Vincenzo Librandi_, Jul 26 2013 *)
%t #+{0,1,3,4,5}&/@(7*Range[0,20])//Flatten (* or *) LinearRecurrence[ {1,0,0,0,1,-1},{0,1,3,4,5,7},80] (* _Harvey P. Dale_, Jun 05 2019 *)
%o (Magma) [n: n in [1..80] | n mod 7 in [0,1,3,4,5]]; // _Vincenzo Librandi_, Jul 26 2013
%K nonn,easy
%O 1,3
%A _N. J. A. Sloane_
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