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 A124864 #12 Apr 30 2025 14:37:07
%S A124864 1,13,59,217,927,4003,17735,79603,361207,1652347,7608009,35214643,
%T A124864 163703859,763777807,3574392251,16771283857,78867271271,371585266531,
%U A124864 1753627967177,8287756490659,39216985201477,185770958749075
%N A124864 Number of base 13 circular n-digit numbers with adjacent digits differing by 2 or less.
%C A124864 [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C A124864 See A285280 for confirmation of linear recurrence and code to produce sequence. - _Ray Chandler_, Aug 12 2023.
%H A124864 Ray Chandler, <a href="/A124864/b124864.txt">Table of n, a(n) for n = 0..99</a>
%H A124864 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>
%H A124864 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (13, -55, 55, 159, -285, -155, 365, 60, -174, -9, 27).
%o A124864 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>2)+($[(i+1)mod N]`-$[i]`>2))
%Y A124864 Cf. Row 13 of A285280.
%K A124864 nonn,base
%O A124864 0,2
%A A124864 _R. H. Hardin_, Dec 28 2006