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%I #15 Sep 08 2022 08:44:48
%S 1,6,33,262,2145,16182,116353,821142,5760705,40347046,282465249,
%T 1977312102,13841266465,96888981846,678223034433,4747561459318,
%U 33232930504065,232630513903686,1628413597805473,11398895185242822
%N a(n) = 7^n - n^4.
%H Vincenzo Librandi, <a href="/A024079/b024079.txt">Table of n, a(n) for n = 0..500</a>
%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (12,-45,80,-75,36,-7).
%F From _Chai Wah Wu_, May 13 2017: (Start)
%F a(n) = 12*a(n-1) - 45*a(n-2) + 80*a(n-3) - 75*a(n-4) + 36*a(n-5) - 7*a(n-6) for n > 5.
%F G.f.: (6*x^5 + 81*x^4 + 56*x^3 + 6*x^2 - 6*x + 1)/((x - 1)^5*(7*x - 1)). (End)
%t Array[7^# - #^4 &, 20, 0] (* or *)
%t CoefficientList[Series[(6 x^5 + 81 x^4 + 56 x^3 + 6 x^2 - 6 x + 1)/((x - 1)^5*(7 x - 1)), {x, 0, 19}], x] (* _Michael De Vlieger_, May 13 2017 *)
%t LinearRecurrence[{12,-45,80,-75,36,-7},{1,6,33,262,2145,16182},20] (* _Harvey P. Dale_, Feb 02 2020 *)
%o (Magma) [7^n-n^4: n in [0..25]]; // _Vincenzo Librandi_, Jul 03 2011
%K nonn,easy
%O 0,2
%A _N. J. A. Sloane_
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