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 A126392 #22 Apr 27 2018 14:59:27
%S A126392 1,5,19,75,295,1161,4569,17981,70763,278483,1095951,4313041,16973681,
%T A126392 66798773,262882051,1034554523,4071419319,16022795225,63056626377,
%U A126392 248155086189,976597549531,3843333571747,15125179200799,59524119253665
%N A126392 Number of base 5 n-digit numbers with adjacent digits differing by two or less.
%C A126392 a(base,n)=a(base-1,n)+5^(n-1) for base>=2n-1; a(base,n)=a(base-1,n)+5^(n-1)-2 when base=2n-2.
%H A126392 S. Kitaev, J. Remmel, <a href="http://arxiv.org/abs/1304.4286">(a,b)-rectangle patterns in permutations and words</a>, arXiv:1304.4286 [math.CO]
%H A126392 <a href="/index/Rec#order_03">Index entries for linear recurrences with constant coefficients</a>, signature (4,0,-1).
%F A126392 a(n) = 4*a(n-1)-a(n-3). G.f.: -(x^2-x-1)/(x^3-4*x+1). [_Colin Barker_, Nov 25 2012]
%t A126392 LinearRecurrence[{4,0,-1},{1,5,19},30] (* _Harvey P. Dale_, Apr 27 2018 *)
%o A126392 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-2](($[i]`-$[i+1]`>2)+($[i+1]`-$[i]`>2))
%Y A126392 Cf. Base 5 differing by one or less A057960.
%K A126392 nonn,base
%O A126392 0,2
%A A126392 _R. H. Hardin_, Dec 28 2006
%E A126392 Edited by _Charles R Greathouse IV_, Aug 05 2010