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 A383198 #17 Aug 05 2025 02:28:55
%S A383198 9,54,328,2000,12202,74458,454366,2772710,16920138,103253214,
%T A383198 630091042,3845059318,23464039746,143186649814,873780342786,
%U A383198 5332145758694,32538816680050,198564450196598,1211717109125762,7394366670845606,45123286657530514,275359755529253142
%N A383198 Number of positive integers with n digits in which adjacent digits differ by at most 3.
%H A383198 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-4,-10,6).
%F A383198 G.f.: -x*(10*x^3-14*x^2-9*x+9)/(6*x^4-10*x^3-4*x^2+7*x-1). - _Alois P. Heinz_, Apr 23 2025
%t A383198 LinearRecurrence[{7,-4,-10,6},{9, 54, 328, 2000},22] (* or *) Rest[CoefficientList[Series[(-x*(10*x^3-14*x^2-9*x+9)/(6*x^4-10*x^3-4*x^2+7*x-1)),{x,0,22}],x]] (* _James C. McMahon_, May 01 2025 *)
%Y A383198 Cf. A235163, A383197, A383199, A383200, A383201, A383202.
%K A383198 nonn,base,easy
%O A383198 1,1
%A A383198 _Edwin Hermann_, Apr 19 2025
%E A383198 More terms from _Alois P. Heinz_, Apr 23 2025