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 A124893 #12 Apr 30 2025 14:45:48
%S A124893 1,15,69,255,1097,4765,21237,95873,437537,2012997,9321899,43397633,
%T A124893 202926209,952396005,4484003747,21168581905,100170213121,474981809053,
%U A124893 2256307682541,10735210220803,51148724456627,244007372314919
%N A124893 Number of base 15 circular n-digit numbers with adjacent digits differing by 2 or less.
%C A124893 [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C A124893 See A285280 for confirmation of linear recurrence and code to produce sequence. - _Ray Chandler_, Aug 12 2023.
%H A124893 Ray Chandler, <a href="/A124893/b124893.txt">Table of n, a(n) for n = 0..99</a>
%H A124893 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 A124893 <a href="/index/Rec#order_15">Index entries for linear recurrences with constant coefficients</a>, signature (15, -78, 130, 176, -682, 44, 1128, -330, -818, 249, 261, -62, -30, 3, 1).
%o A124893 (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 A124893 Cf. Row 15 of A285280.
%K A124893 nonn,base
%O A124893 0,2
%A A124893 _R. H. Hardin_, Dec 28 2006