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 A025923 Expansion of 1/((1-x^9)*(1-x^10)*(1-x^11)). 0

%I #11 Feb 28 2020 08:17:52

%S 1,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,1,1,2,1,1,0,0,0,0,1,1,2,2,2,1,1,

%T 0,0,1,1,2,2,3,2,2,1,1,1,1,2,2,3,3,3,2,2,2,2,2,2,3,3,4,3,3,3,3,3,3,3,

%U 3,4,4,4,4,4,4,4,4,4,4,4

%N Expansion of 1/((1-x^9)*(1-x^10)*(1-x^11)).

%H <a href="/index/Rec#order_30">Index entries for linear recurrences with constant coefficients</a>, signature (0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,-1,-1,-1,0,0,0,0,0,0,0,0,1).

%F a(n) = a(n-9) + a(n-10) + a(n-11) - a(n-19) - a(n-20) - a(n-21) + a(n-30). - _R. J. Mathar_, Jul 19 2014

%t CoefficientList[1/Series[Times@@(1-x^Range[9,11]),{x,0,120}],x] (* or *) LinearRecurrence[{0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,0,-1,-1,-1,0,0,0,0,0,0,0,0,1},{1,0,0,0,0,0,0,0,0,1,1,1,0,0,0,0,0,0,1,1,2,1,1,0,0,0,0,1,1,2},120] (* _Harvey P. Dale_, Apr 01 2018 *)

%o (PARI) Vec(1/((1-x^9)*(1-x^10)*(1-x^11)) + O(x^90)) \\ _Jinyuan Wang_, Feb 28 2020

%K nonn

%O 0,21

%A _N. J. A. Sloane_

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Last modified March 5 09:09 EST 2024. Contains 370545 sequences. (Running on oeis4.)