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 A125373 #24 Apr 30 2025 15:25:37 %S A125373 1,10,80,580,4660,37960,311378,2559658,21057948,173287588,1426133270, %T A125373 11737272106,96600478510,795047628502,6543462720560,53854541701240, %U A125373 443238127915788,3647975524214452,30023874009147704,247105006940966092 %N A125373 Number of base 10 circular n-digit numbers with adjacent digits differing by 5 or less. %C A125373 [Empirical] a(base,n)=a(base-1,n)+F(5) for base>=5.int(n/2)+1 and F(d) is the largest coefficient in (1+x+...+x^(2d))^n %H A125373 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 A125373 <a href="/index/Rec#order_08">Index entries for linear recurrences with constant coefficients</a>, signature (11, -21, -19, 34, 8, -15, -1, 2). %F A125373 G.f.: (1 - x - 9*x^2 - 71*x^3 + 116*x^4 + 52*x^5 - 87*x^6 - 9*x^7 + 16*x^8)/((1 + x)(1 - 3*x + x^3)(1 - 9*x + 6*x^2 + 3*x^3 - 2*x^4)). For n<4, a(n) = 5*6^n-4*5^n = A257286(n). - _M. F. Hasler_, May 03 2015 %t A125373 LinearRecurrence[{11,-21,-19,34,8,-15,-1,2},{1,10,80,580,4660,37960,311378,2559658,21057948},30] (* _Harvey P. Dale_, May 14 2018 *) %o A125373 (S/R) stvar $[N]:(0..M-1) init $[]:=0 asgn $[]->{*} kill +[i in 0..N-1](($[i]`-$[(i+1)mod N]`>5)+($[(i+1)mod N]`-$[i]`>5)) %K A125373 nonn,base %O A125373 0,2 %A A125373 _R. H. Hardin_, Dec 28 2006