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 A170938 #14 Apr 30 2016 18:41:03
%S A170938 4,8,22,74,274,1058,4162,16514,65794,262658,1049602,4196354,16781314,
%T A170938 67117058,268451842,1073774594,4295032834,17180000258,68719738882,
%U A170938 274878431234,1099512676354,4398048608258,17592190238722,70368752566274,281474993487874,1125899940397058
%N A170938 4^n+2^n+2.
%H A170938 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (7,-14,8).
%F A170938 a(n)= 7*a(n-1) -14*a(n-2) +8*a(n-3). G.f.: 2*(2-10*x+11*x^2)/((1-x) * (2*x-1) * (4*x-1)). [From _R. J. Mathar_, Feb 15 2010]
%t A170938 Table[4^n+2^n+2,{n,0,30}] (* or *) LinearRecurrence[{7,-14,8},{4,8,22},30] (* _Harvey P. Dale_, Jan 10 2013 *)
%K A170938 nonn,easy
%O A170938 0,1
%A A170938 _N. J. A. Sloane_, Feb 13 2010