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 A155618 #14 Apr 12 2017 17:39:52
%S A155618 1,10,64,406,2656,17830,121744,839926,5830336,40615750,283523824,
%T A155618 1981521046,13858064416,96956119270,678491508304,4748635251766,
%U A155618 33237225536896,232647693856390,1628482317387184,11399170063280086
%N A155618 a(n) = 7^n+4^n-1^n.
%H A155618 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (12,-39,28).
%F A155618 G.f.: 1/(1-7*x)+1/(1-4*x)-1/(1-x). E.g.f.: e^(7*x)+e^(4*x)-e^x.
%F A155618 a(n) = 11*a(n-1)-28*a(n-2)-18 with a(0)=1, a(1)=10 [_Vincenzo Librandi_, Jul 21 2010]
%F A155618 a(0)=1, a(1)=10, a(2)=64, a(n) = 12*a(n-1)-39*a(n-2)+28*a(n-3). - _Harvey P. Dale_, Feb 04 2014
%p A155618 A155618:=n->7^n+4^n-1: seq(A155618(n), n=0..30); # _Wesley Ivan Hurt_, Apr 11 2017
%t A155618 Table[7^n+4^n-1,{n,0,20}] (* or *) LinearRecurrence[{12,-39,28},{1,10,64},20] (* _Harvey P. Dale_, Feb 04 2014 *)
%Y A155618 A155588, A155599, A155607, A155608, A155609, A155610, A155611, A155612, A155613, A155614, A155615, A155616, A155617
%K A155618 nonn
%O A155618 0,2
%A A155618 _Mohammad K. Azarian_, Jan 27 2009