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 A168097 #14 Jun 29 2023 12:52:02
%S A168097 7,8,9,10,11,12,13,14,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
%T A168097 15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,15,
%U A168097 15,15,15,15,15,15,15,15
%N A168097 a(n) = number of natural numbers m such that n - 7 <= m <= n + 7.
%C A168097 Generalization: If a(n,k) = number of natural numbers m such that n - k <= m <= n + k (k >= 1) then a(n,k) = a(n-1,k) + 1 = n + k for 0 <= n <= k, a(n,k) = a(n-1,k) = 2k + 1 for n >= k + 1 (see, e.g., A158799).
%H A168097 <a href="/index/Rec#order_01">Index entries for linear recurrences with constant coefficients</a>, signature (1).
%F A168097 a(n) = 7 + n for 0 <= n <= 7, a(n) = 15 for n >= 8.
%F A168097 G.f.: (7 - 6*x - x^9)/(1-x)^2. - _G. C. Greubel_, Jul 12 2016
%t A168097 CoefficientList[Series[(7 - 6*x - x^9)/(1 - x)^2, {x, 0, 25}], x] (* _G. C. Greubel_, Jul 12 2016 *)
%Y A168097 Cf. A000027.
%K A168097 nonn,less
%O A168097 0,1
%A A168097 _Jaroslav Krizek_, Nov 18 2009