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 A139745 #24 Apr 02 2025 18:32:44
%S A139745 0,4,72,988,12240,144244,1653912,18663628,208594080,2317594084,
%T A139745 25654949352,283334343868,3124587089520,34425823133524,
%U A139745 379071610510392,4172500607905708,45916496933002560,505214397985306564,5558288899894321032,61147691553229173148,672670202666262397200
%N A139745 a(n) = 11^n - 7^n.
%H A139745 Vincenzo Librandi, <a href="/A139745/b139745.txt">Table of n, a(n) for n = 0..300</a>
%H A139745 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (18,-77).
%F A139745 a(n) = 18*a(n-1) - 77*a(n-2). - _Vincenzo Librandi_, Jun 02 2011
%F A139745 From _Stefano Spezia_, Mar 09 2025: (Start)
%F A139745 G.f.: 4*x/((1 - 11*x)*(1 - 7*x)).
%F A139745 E.g.f.: exp(7*x)*(exp(4*x) - 1). (End)
%F A139745 a(n) = 4*A016183(n-1) for n >= 1. - _Elmo R. Oliveira_, Apr 01 2025
%t A139745 Table[11^n-7^n,{n,0,30}] (* or *) LinearRecurrence[{18,-77},{0,4},30] (* _Harvey P. Dale_, Jun 17 2014 *)
%o A139745 (Magma) [11^n-7^n: n in [0..30]]; // _Vincenzo Librandi_, Jun 02 2011
%Y A139745 Cf. A000420, A001020, A016183.
%K A139745 nonn,easy
%O A139745 0,2
%A A139745 _N. J. A. Sloane_, May 20 2008