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 A139740 #44 Mar 16 2025 18:37:11
%S A139740 0,9,117,1323,14625,161019,1771497,19487043,214358625,2357947179,
%T A139740 25937423577,285311668563,3138428372625,34522712135739,
%U A139740 379749833566857,4177248169382883,45949729863506625,505447028499162699,5559917313491969337,61159090448414022003,672749994932558960625
%N A139740 a(n) = 11^n - 2^n.
%H A139740 Vincenzo Librandi, <a href="/A139740/b139740.txt">Table of n, a(n) for n = 0..300</a>
%H A139740 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (13,-22).
%F A139740 a(n) = 13*a(n-1) - 22*a(n-2). - _Vincenzo Librandi_, Jun 02 2011
%F A139740 a(n) = A001020(n) - A000079(n). - _Michel Marcus_, Feb 28 2022
%F A139740 a(n) = 9*A016135(n-1), n > 0. - _Bernard Schott_, Mar 09 2022
%F A139740 E.g.f.: exp(2*x)*(exp(9*x) - 1). - _Stefano Spezia_, Mar 09 2025
%F A139740 G.f.: 9*x/((1-2*x)*(1-11*x)). - _Elmo R. Oliveira_, Mar 15 2025
%t A139740 Table[11^n - 2^n, {n, 0, 20}] (* or *)
%t A139740 LinearRecurrence[{13, -22}, {0, 9}, 21] (* _Paolo Xausa_, Mar 16 2025 *)
%o A139740 (Sage) [11^n - 2^n for n in range(0,20)] # _Zerinvary Lajos_, Jun 05 2009
%o A139740 (Magma) [11^n-2^n: n in [0..30]]; // _Vincenzo Librandi_, Jun 02 2011
%o A139740 (PARI) a(n)=11^n-2^n \\ _Charles R Greathouse IV_, Mar 26 2012
%o A139740 (Python) [11**n-2**n for n in range(20)] # _Gennady Eremin_, Mar 05 2022
%Y A139740 Cf. A000079, A001020, A016135.
%K A139740 nonn,easy
%O A139740 0,2
%A A139740 _N. J. A. Sloane_, May 20 2008