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a(n) = n^5-n^4-n^3-n^2-n-1.
5

%I #13 Sep 08 2022 08:45:28

%S -1,-4,1,122,683,2344,6221,14006,28087,51668,88889,144946,226211,

%T 340352,496453,705134,978671,1331116,1778417,2338538,3031579,3879896,

%U 4908221,6143782,7616423,9358724,11406121,13797026,16572947,19778608,23462069,27674846,32472031,37912412,44058593

%N a(n) = n^5-n^4-n^3-n^2-n-1.

%C More generally, the ordinary generating function for the values of quintic polynomial b*n^5 + p*n^4 + q*n^3 + k*n^2 + m*n + r, is (r + (b + p + q + k + m - 5*r)*x + (13*b + 5*p + q - k - 2*m + 5*r)*2*x^2 + (33*b - 3*q + 3*m - 5*r)*2*x^3 + (26*b - 10*p + 2*q + 2*k - 4*m + 5*r)*x^4 + (b - p + q - k + m - r)*x^5)/(1 - x)^6. - _Ilya Gutkovskiy_, Mar 31 2016

%H Vincenzo Librandi, <a href="/A125083/b125083.txt">Table of n, a(n) for n = 0..580</a>

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (6,-15,20,-15,6,-1)

%F G.f.: (-1 + 2*x + 10*x^2 + 76*x^3 + 31*x^4 + 2*x^5)/(1 - x)^6. - _Ilya Gutkovskiy_, Mar 31 2016

%t Table[n^5 - n^4 - n^3 - n^2 - n - 1, {n, 0, 41}]

%o (Magma) [n^5-n^4-n^3-n^2-n-1: n in [0..60]]; // _Vincenzo Librandi_, Apr 26 2011

%o (PARI) a(n) = n^5-n^4-n^3-n^2-n-1; \\ _Michel Marcus_, Mar 31 2016

%Y Cf. A125082, A083074.

%K sign,easy

%O 0,2

%A _Artur Jasinski_, Nov 19 2006