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 A125319 #13 Apr 30 2025 15:01:01
%S A125319 1,9,51,249,1387,7879,45663,267367,1575395,9316455,55211811,327600447,
%T A125319 1945195699,11554693471,68652279747,407952680479,2424365629955,
%U A125319 14408066169471,85629681584835,508919764066431,3024669695471107
%N A125319 Number of base 9 circular n-digit numbers with adjacent digits differing by 3 or less.
%C A125319 [Empirical] a(base,n)=a(base-1,n)+A025012(n+1) for base>=3.int(n/2)+1
%H A125319 OEIS Wiki, <a href="/wiki/Number_of_base_k_circular_n-digit_numbers_with_adjacent_digits_differing_by_d_or_less">Number of base k circular n-digit numbers with adjacent digits differing by d or less</a>
%F A125319 G.f.: (1 - x - 14*x^2 - 36*x^3 + 138*x^4 - 58*x^5 - 52*x^6 + 28*x^7) / ((1 - x)*(1 + x)*(1 - 4*x + 2*x^2)*(1 - 6*x + 2*x^3)) (conjectured). - _Colin Barker_, Jun 02 2017
%o A125319 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>3)+($[(i+1)mod N]`-$[i]`>3))
%K A125319 nonn,base
%O A125319 0,2
%A A125319 _R. H. Hardin_, Dec 28 2006