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%I #17 Mar 29 2023 17:36:26
%S 1,2,3,6,7,9,10,11,14,15,17,18,19,22,23,25,26,27,30,31,33,34,35,38,39,
%T 41,42,43,46,47,49,50,51,54,55,57,58,59,62,63,65,66,67,70,71,73,74,75,
%U 78,79,81,82,83,86,87,89
%N Numbers that are congruent to {1, 2, 3, 6, 7} mod 8.
%H G. C. Greubel, <a href="/A047561/b047561.txt">Table of n, a(n) for n = 1..1000</a>
%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,0,1,-1).
%F From _Chai Wah Wu_, May 29 2016: (Start)
%F a(n) = a(n-1) + a(n-5) - a(n-6) for n>6.
%F G.f.: x*(x^5 + x^4 + 3*x^3 + x^2 + x + 1)/(x^6 - x^5 - x + 1). (End)
%t LinearRecurrence[{1, 0, 0, 0, 1, -1}, {1, 2, 3, 6, 7, 9}, 50] (* _G. C. Greubel_, May 29 2016 *)
%t #+{1,2,3,6,7}&/@(8*Range[0,20])//Flatten (* _Harvey P. Dale_, Mar 29 2023 *)
%o (Magma) [n : n in [0..150] | n mod 8 in [1, 2, 3, 6, 7]]; // _Wesley Ivan Hurt_, May 29 2016
%K nonn,easy
%O 1,2
%A _N. J. A. Sloane_