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 A155645 #19 Aug 31 2025 21:01:47
%S A155645 1,12,84,558,3696,24582,164304,1103478,7444416,50431302,342941424,
%T A155645 2340123798,16018069536,109949704422,756587236944,5217746494518,
%U A155645 36054040477056,249557173431942,1729973554578864,12008254925383638
%N A155645 a(n) = 7^n+6^n-1.
%H A155645 <a href="/index/Rec">Index entries for linear recurrences with constant coefficients</a>, signature (14,-55,42).
%F A155645 G.f.: 1/(1-7*x)+1/(1-6*x)-1/(1-x).
%F A155645 E.g.f.: e^(7*x)+e^(6*x)-e^x.
%F A155645 a(n) = 13*a(n-1)-42*a(n-2)-30 with a(0)=1, a(1)=12. - _Vincenzo Librandi_, Jul 21 2010
%F A155645 a(0)=1, a(1)=12, a(2)=84, a(n) = 14*a(n-1)-55*a(n-2)+42*a(n-3). - _Harvey P. Dale_, May 08 2012
%t A155645 Table[7^n+6^n-1,{n,0,20}] (* or *) LinearRecurrence[{14,-55,42},{1,12,84},20] (* _Harvey P. Dale_, May 08 2012 *)
%o A155645 (PARI) a(n)=7^n+6^n-1 \\ _Charles R Greathouse IV_, Jun 11 2015
%Y A155645 Cf. A155628, A155629, A155630, A155631, A155632, A155633, A155634, A155635, A155636, A155637, A155638, A155639, A155640, A155641, A155642, A155643, A155644.
%K A155645 nonn,easy,changed
%O A155645 0,2
%A A155645 _Mohammad K. Azarian_, Jan 31 2009