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 A260030 #14 Jan 18 2025 16:34:59 %S A260030 12,1100,10001001100,1001010100000110110010101010001100 %N A260030 Convert the last term from decimal to binary! a(1)=12. %C A260030 The next term has 110 digits. - _Harvey P. Dale_, May 15 2018 %t A260030 NestList[FromDigits[IntegerDigits[#,2]]&,12,4] (* _Harvey P. Dale_, May 15 2018 *) %Y A260030 For initial terms 2 through 12 see A008559, A006938, A260025, A260024, A260026, A260027, A260028, A260029, A008559 (again), A006938 (again), A260030 respectively. %K A260030 nonn,base %O A260030 1,1 %A A260030 _N. J. A. Sloane_, Jul 14 2015