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 A124857 #12 Apr 30 2025 14:36:07
%S A124857 1,11,49,179,757,3241,14233,63333,284877,1291697,5894119,27031653,
%T A124857 124481521,575160311,2664800299,12374329729,57568895517,268238883291,
%U A124857 1251429223153,5844466935453,27318547433927,127784523940077
%N A124857 Number of base 11 circular n-digit numbers with adjacent digits differing by 2 or less.
%C A124857 [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C A124857 See A285280 for confirmation of linear recurrence and code to produce sequence. - _Ray Chandler_, Aug 12 2023.
%H A124857 Ray Chandler, <a href="/A124857/b124857.txt">Table of n, a(n) for n = 0..99</a>
%H A124857 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 A124857 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (11, -36, 12, 105, -77, -102, 66, 35, -15, -3, 1).
%o A124857 (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 A124857 Cf. Row 11 of A285280.
%K A124857 nonn,base
%O A124857 0,2
%A A124857 _R. H. Hardin_, Dec 28 2006