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 A308529 #21 Jun 15 2019 10:25:16 %S A308529 0,2,4,10,18,34,62,118,222,432,834,1642,3230,6406,12702,25298,50386, %T A308529 100566,200716,401022,801230,1601654,3201694,6401784,12800378, %U A308529 25597578,51188806,102371284,204729938,409447272,818869352,1637713546,3275376848,6550703506,13101306654,26202513022,52404825604,104809450870,209618501128,419236601774 %N A308529 Number of length-n binary words having exactly one nontrivial palindrome prefix. %C A308529 A palindrome is nontrivial if it is of length at least 2. %e A308529 For n = 4 the 10 solutions are 0010, 0011, 0100, 0101, 0110 and their binary complements. %Y A308529 Cf. A308528. %K A308529 nonn %O A308529 1,2 %A A308529 _Jeffrey Shallit_, Jun 06 2019 %E A308529 a(29)-a(40) from _Bert Dobbelaere_, Jun 15 2019