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 A254657 #16 Sep 08 2022 08:46:11
%S A254657 1,9,78,678,5892,51204,444984,3867096,33606672,292055952,2538087648,
%T A254657 22057036896,191684821056,1665820789824,14476675244928,
%U A254657 125808326698368,1093326665056512,9501463280642304,82571666235477504,717582109567673856,6236086873954255872
%N A254657 Numbers of words on alphabet {0,1,...,8} with no subwords ii, where i is from {0,1,2}.
%H A254657 Colin Barker, <a href="/A254657/b254657.txt">Table of n, a(n) for n = 0..1000</a>
%H A254657 <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (8,6).
%F A254657 G.f.: (1 + x)/(1 - 8*x - 6*x^2).
%F A254657 a(n) = 8*a(n-1) + 6*a(n-2) with n>1, a(0) = 1, a(1) = 9.
%F A254657 a(n) = (((4-sqrt(22))^n*(-5+sqrt(22)) + (4+sqrt(22))^n*(5+sqrt(22))))/(2*sqrt(22)). - _Colin Barker_, Nov 16 2016
%t A254657 RecurrenceTable[{a[0] == 1, a[1] == 9, a[n] == 8 a[n - 1] + 6 a[n - 2]}, a[n], {n, 0, 20}]
%o A254657 (Magma) [n le 1 select 9^n else 8*Self(n)+6*Self(n-1): n in [0..20]];
%o A254657 (PARI) Vec((1+x)/(1-8*x-6*x^2) + O(x^30)) \\ _Colin Barker_, Nov 16 2016
%Y A254657 Cf. A055099, A126473, A126501, A126528, A190560, A254598, A254602.
%K A254657 nonn,easy
%O A254657 0,2
%A A254657 _Milan Janjic_, Feb 04 2015