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 A088953 #8 Feb 16 2025 08:32:51 %S A088953 1,3,4,8,12,20,28,40,52,72,96,136,176,228,304,412,532,696,928,1220, %T A088953 1592,2120,2764,3612,4688,6132,7928,10324,13480,17616,22948,29908, %U A088953 38964,50748,66184,86344,112364,146344,190500 %N A088953 Number of numbers that are ternary squarefree words of length n. %H A088953 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquarefreeWord.html">Squarefree Word</a> %F A088953 a(n) = A006156(n)*2/3 for n>1 [Corrected by _Rémy Sigrist_, Aug 19 2020]. %Y A088953 Cf. A088952, A007089. %K A088953 nonn %O A088953 0,2 %A A088953 _Reinhard Zumkeller_, Oct 25 2003