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 A124956 #12 Apr 30 2025 14:52:53
%S A124956 1,28,134,502,2202,9718,44000,201628,933682,4357222,20462184,96587068,
%T A124956 457871484,2178414292,10396478562,49751026042,238639567362,
%U A124956 1147064158822,5523799769432,26644582803412,128714976934252
%N A124956 Number of base 28 circular n-digit numbers with adjacent digits differing by 2 or less.
%C A124956 [Empirical] a(base,n)=a(base-1,n)+A005191(n+1) for base>=2.int(n/2)+1.
%C A124956 See A285280 for confirmation of linear recurrence and code to produce sequence. - _Ray Chandler_, Aug 12 2023.
%H A124956 Ray Chandler, <a href="/A124956/b124956.txt">Table of n, a(n) for n = 0..99</a>
%H A124956 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 A124956 <a href="/index/Rec#order_26">Index entries for linear recurrences with constant coefficients</a>, signature (28, -325, 1950, -5726, 2048, 36431, -83710, -39915, 347244, -179931, -699022, 681580, 825120, -1075801, -606254, 967407, 279940, -527440, -79152, 173157, 12824, -32375, -1050, 3045, 36, -108).
%o A124956 (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 A124956 Cf. Row 28 of A285280.
%K A124956 nonn,base
%O A124956 0,2
%A A124956 _R. H. Hardin_, Dec 28 2006