This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A024121 #50 Sep 08 2022 08:44:48
%S A024121 1,9,-28,-1187,-6384,21875,720064,9176457,97902848,995217031,
%T A024121 9990000000,99980512829,999964168192,9999937251483,99999894586496,
%U A024121 999999829140625,9999999731564544,99999999589661327,999999999387779968
%N A024121 a(n) = 10^n - n^7.
%H A024121 Vincenzo Librandi, <a href="/A024121/b024121.txt">Table of n, a(n) for n = 0..300</a>
%H A024121 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (18,-108,336,-630,756,-588,288,-81,10).
%F A024121 From _Stefano Spezia_, Oct 04 2018: (Start)
%F A024121 a(n) = 18*a(n - 1) - 108*a(n - 2) + 336*a(n - 3) - 630*a(n - 4) + 756*a(n - 5) - 588*a(n - 6) + 288*a(n - 7) - 81*a(n - 8) + 10*a(n - 9) for n > 8.
%F A024121 G.f.: -((1 - 9*x - 82*x^2 - 47*x^3 + 9564*x^4 + 22913*x^5 + 11818*x^6 + 1191*x^7 + 11*x^8)/((-1 + x)^8*(-1 + 10*x))).
%F A024121 E.g.f.: exp(x)*(exp(9*x) - x - 63*x^2 - 301*x^3 - 350*x^4 - 140*x^5 - 21*x^6 - x^7).
%F A024121 (End)
%p A024121 seq(10^n-n^7,n=0..20); # _Muniru A Asiru_, Oct 16 2018
%t A024121 a[n_]:=10^n - n^7; Array[a, 50, 0] (* _Stefano Spezia_, Oct 04 2018 *)
%t A024121 LinearRecurrence[{18,-108,336,-630,756,-588,288,-81,10},{1,9,-28,-1187,-6384,21875,720064,9176457,97902848},20] (* _Harvey P. Dale_, Sep 16 2021 *)
%o A024121 (Magma) [10^n-n^7: n in [0..20]]; // _Vincenzo Librandi_, Jul 01 2011
%o A024121 (PARI) a(n)=10^n-n^7 \\ _Charles R Greathouse IV_, Jul 01 2011
%o A024121 (GAP) List([0..20],n->10^n-n^7); # _Muniru A Asiru_, Oct 16 2018
%Y A024121 Cf. A011557 (10^n), A001015 (n^7).
%K A024121 sign,easy
%O A024121 0,2
%A A024121 _N. J. A. Sloane_