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%I #17 Mar 14 2024 10:40:57
%S 121,121,120,118,115,111,106,100,93,85,76,66,55,43,30,16,1,-15,-32,
%T -50,-69,-89,-110,-132,-155,-179,-204,-230,-257,-285,-314,-344,-375,
%U -407,-440,-474,-509,-545,-582,-620,-659,-699,-740,-782,-825,-869,-914,-960
%N a(0) = 121; for n>0, a(n) = a(n-1) - n + 1.
%H G. C. Greubel, <a href="/A137517/b137517.txt">Table of n, a(n) for n = 0..1000</a>
%H <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (3,-3,1).
%F a(n) = (1/2)*(242 - n^2 + n) - _Alexander R. Povolotsky_, Apr 26 2008
%F a(0)=121, a(1)=121, a(2)=120, a(n)=3*a(n-1)-3*a(n-2)+a(n-3). - _Harvey P. Dale_, Dec 07 2012
%F G.f.: -(12*x-11)*(10*x-11) / (x-1)^3 . - _R. J. Mathar_, Nov 07 2015
%t RecurrenceTable[{a[0]==121,a[n]==a[n-1]-n+1},a,{n,60}] (* or *) LinearRecurrence[{3,-3,1},{121,121,120},60] (* _Harvey P. Dale_, Dec 07 2012 *)
%t CoefficientList[Series[-(12*x - 11)*(10*x - 11)/(x - 1)^3, {x,0,50}], x] (* _G. C. Greubel_, Feb 23 2017 *)
%o (PARI) my(x='x + O('x^50)); Vec(-(12*x - 11)*(10*x - 11)/(x - 1)^3) \\ _G. C. Greubel_, Feb 23 2017
%K sign,easy
%O 0,1
%A Frederic Sebastian (frederic.sebastian(AT)gmail.com), Apr 24 2008
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