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%I #37 Sep 08 2022 08:46:14
%S 1,1,3,5,7,9,13,19,27,39,57,83,119,171,247,357,515,743,1073,1549,2235,
%T 3225,4655,6719,9697,13995,20199,29153,42075,60725,87643,126493,
%U 182563,263487,380283,548851,792139,1143269,1650045,2381459,3437085,4960637,7159533
%N a(n) = a(n-7) + a(n-4) + a(n-1) for n>1 and a(n)=1 for n<=1.
%H <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (1,0,0,1,0,0,1).
%F a(n) = a(n-7) + a(n-4) + a(n-1) for n>1 and a(n)=1 for n<=1.
%F G.f.: (1+2*x^2+2*x^3+x^4+x^5+x^6) / (1-x-x^4-x^7). - _Wesley Ivan Hurt_, Oct 08 2015
%t LinearRecurrence[{1, 0, 0, 1, 0, 0, 1}, {1, 1, 3, 5, 7, 9, 13}, 50] (* or *) CoefficientList[Series[(1 + 2*x^2 + 2*x^3 + x^4 + x^5 + x^6)/(1 - x - x^4 - x^7), {x, 0, 50}], x] (* _Wesley Ivan Hurt_, Oct 08 2015 *)
%o (R) a<- (function(n) {if (n < 2) return(1); a(n-7) + a(n-4) + a(n-1)})
%o (Magma) I:=[1,3,5,7,9,13,19]; [n le 7 select I[n] else Self(n-7)+Self(n-4)+Self(n-1): n in [1..40]]; // _Vincenzo Librandi_, Oct 09 2015
%K nonn,easy
%O 0,3
%A _Tobias Kind_, Sep 25 2015
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