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 A383197 #17 Apr 23 2025 13:10:04 %S A383197 9,41,188,867,4010,18574,86096,399225,1851529,8587802,39833891, %T A383197 184770640,857073208,3975623218,18441391129,85542653145,396800342804, %U A383197 1840608838251,8537899488042,39604141848678,183708898915088,852157340908409,3952841397780937,18335763176322738 %N A383197 Number of positive integers with n digits in which adjacent digits differ by at most 2. %H A383197 <a href="/index/Rec#order_04">Index entries for linear recurrences with constant coefficients</a>, signature (7,-11,0,1). %F A383197 G.f.: -x*(2*x^3-22*x+9)/(x^4-11*x^2+7*x-1). - _Alois P. Heinz_, Apr 21 2025 %Y A383197 Cf. A235163, A383198, A383199, A383200, A383201, A383202. %K A383197 nonn,base,easy %O A383197 1,1 %A A383197 _Edwin Hermann_, Apr 19 2025 %E A383197 a(15)-a(24) from _Alois P. Heinz_, Apr 21 2025