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 A124852 #17 Apr 30 2025 14:35:24
%S A124852 1,10,44,160,672,2860,12482,55198,246712,1111372,5037174,22940158,
%T A124852 104870790,480863770,2210197754,10178143810,46942294232,216761695840,
%U A124852 1001878336772,4634206919128,21448419453382,99316222901062
%N A124852 Number of base 10 circular n-digit numbers with adjacent digits differing by 2 or less.
%C A124852 [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C A124852 See A285280 for confirmation of linear recurrence and code to produce sequence; also confirms conjectured g.f. from _Colin Barker_. - _Ray Chandler_, Aug 12 2023.
%H A124852 Ray Chandler, <a href="/A124852/b124852.txt">Table of n, a(n) for n = 0..99</a>
%H A124852 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 A124852 <a href="/index/Rec#order_09">Index entries for linear recurrences with constant coefficients</a>, signature (11, -39, 39, 37, -65, 4, 16, -1, -1).
%F A124852 G.f.: (1 - x - 27*x^2 + 27*x^3 + 201*x^4 - 313*x^5 + 8*x^6 + 112*x^7 - 7*x^8 - 9*x^9) / ((1 - x)*(1 + x)*(1 - 4*x + x^2 + x^3)*(1 - 7*x + 11*x^2 - x^4)). - _Colin Barker_, Jun 01 2017
%o A124852 (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 A124852 Cf. Row 10 of A285280.
%K A124852 nonn,base
%O A124852 0,2
%A A124852 _R. H. Hardin_, Dec 28 2006