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 A260025 #17 Jan 19 2025 01:32:32 %S A260025 4,100,1100100,100001100100101000100, %T A260025 1010110101111001011010001101011011001100110110011001100101110100100 %N A260025 Convert the last term from decimal to binary! a(1)=4. %t A260025 NestList[FromDigits[IntegerDigits[#,2]]&,4,5] (* _Harvey P. Dale_, Jun 11 2017 *) %o A260025 (PARI) a(n) = my(k=4); for(i=2, n, k=fromdigits(binary(k))); k; \\ _Jinyuan Wang_, Jan 18 2025 %Y A260025 For initial terms 2 through 12 see A008559, A006938, A260025, A260024, A260026, A260027, A260028, A260029, A008559 (again), A006938 (again), A260030 respectively. %K A260025 nonn,base %O A260025 1,1 %A A260025 _N. J. A. Sloane_, Jul 14 2015