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a(n) = 7^n - 6^n - 5^n - 4^n - 3^n - 2^n.
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%I #21 Apr 10 2024 10:32:35

%S 127,4607,50479,446783,3622207,28040447,211134799,1561328063,

%T 11403051487,82538901887,593482158319,4245770823743,30254894691967,

%U 214923605948927,1522969836817039,10770185918341823,76039637426447647,536127667775741567

%N a(n) = 7^n - 6^n - 5^n - 4^n - 3^n - 2^n.

%C For n < 4, a(n) are negative and not entered here. - _Michel Marcus_, Nov 16 2013

%H <a href="/index/Rec#order_06">Index entries for linear recurrences with constant coefficients</a>, signature (27,-295,1665,-5104,8028,-5040).

%F G.f.: x^4*(488880*x^5-572076*x^4+231460*x^3-36445*x^2+1178*x+127)/((2*x-1)*(3*x-1)*(4*x-1)*(5*x-1)*(6*x-1)*(7*x-1)). - _Colin Barker_, Nov 05 2012

%F a(n) = A000420(n) - A001553(n) + 1. - _Michel Marcus_, Nov 16 2013

%p A137789:=n->7^n-6^n-5^n-4^n-3^n-2^n; seq(A137789(n), n=4..50); # _Wesley Ivan Hurt_, Nov 15 2013

%t Table[7^n - 6^n - 5^n - 4^n - 3^n - 2^n, {n, 4, 30}] (* _Stefan Steinerberger_, May 02 2008 *)

%K nonn,easy

%O 4,1

%A _Vladimir Joseph Stephan Orlovsky_, Apr 28 2008

%E More terms from _Stefan Steinerberger_, May 02 2008