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 A383072 #23 Apr 15 2025 22:06:17
%S A383072 9,36,166,722,3224,14236,63172,279728,1239800,5492776,24339328,
%T A383072 107843024,477848240,2117296288,9381580672,41568964736,184188672416,
%U A383072 816124473376,3616179527008,16022988545120,70996522976672,314579653288672,1393876135246624,6176148562918496
%N A383072 Number of n-digit positive integers where all pairs of consecutive digits have a difference of at least 4.
%H A383072 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (3,8,-6,-6).
%F A383072 G.f.: x*(10*x^3+14*x^2-9*x-9)/(-6*x^4-6*x^3+8*x^2+3*x-1). - _Alois P. Heinz_, Apr 15 2025
%t A383072 LinearRecurrence[{3,8,-6,-6},{9, 36, 166, 722},24] (* or *) Rest[CoefficientList[Series[x*(10*x^3+14*x^2-9*x-9)/(-6*x^4-6*x^3+8*x^2+3*x-1),{x,0,24}] ,x]] (* _James C. McMahon_, Apr 15 2025 *)
%Y A383072 Cf. A052268, A100062, A383070, A383071.
%K A383072 nonn,base,easy
%O A383072 1,1
%A A383072 _Edwin Hermann_, Apr 15 2025
%E A383072 More terms from _Alois P. Heinz_, Apr 15 2025