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 A124799 #12 Apr 30 2025 14:05:49
%S A124799 1,30,88,204,548,1460,4006,11090,31036,87468,248018,706670,2021738,
%T A124799 5804010,16711552,48241364,139572076,404612780,1175026834,3417771710,
%U A124799 9955368238,29035695998,84784671532,247838482400,725183659570
%N A124799 Number of base 30 circular n-digit numbers with adjacent digits differing by 1 or less.
%C A124799 [Empirical] a(base,n)=a(base-1,n)+A002426(n+1) for base>=1.int(n/2)+1
%C A124799 a(n) = T(n, 30) where T(n, k) = Sum_{j=1..k} (1+2*cos(j*Pi/(k+1)))^n. These are the number of smooth cyclic words of length n over the alphabet {1,2,..,30}. See theorem 3.3 in Knopfmacher and others, reference in A124696. - _Peter Luschny_, Aug 13 2012
%H A124799 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>
%o A124799 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>1)+($[(i+1)mod N]`-$[i]`>1))
%K A124799 nonn,base
%O A124799 0,2
%A A124799 _R. H. Hardin_, Dec 28 2006