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 A268610 #41 Aug 02 2025 11:35:01
%S A268610 1,2,3,6,9,18,36,72,99,198,396,792,999,1998,3996,7992,9999,10989,
%T A268610 19998,21978,39996,43956,76923,99999,199998,399996,729927,999999
%N A268610 Indices of records in A004290.
%C A268610 a(n+1) <= 2*a(n) for all n >= 2.
%e A268610 6 is a term because A004290(n) < A004290(6) for all n < 6, where A004290(n) is the least positive multiple of n that when written in base 10 uses only 0's and 1's.
%o A268610 (PARI) lista(nn) = {my(k, r=0); for(n=1, nn, k=1; while(fromdigits(binary(k))%n>0, k++); if(k>r, r=k; print1(n, ", "))); } \\ _Jinyuan Wang_, May 16 2020; a(1)=0 inserted by _Georg Fischer_, Jun 24 2020; a(1)=0 removed again by _David A. Corneth_, Feb 19 2024
%Y A268610 Cf. A004290, A268609.
%K A268610 nonn,base,more
%O A268610 1,2
%A A268610 _David Radcliffe_, Feb 08 2016
%E A268610 a(1)=0 inserted by _Georg Fischer_, Jun 24 2020
%E A268610 Initial 0 removed for consistency with change in A004290 by _Sean A. Irvine_, Feb 19 2024
%E A268610 a(26)-a(28) from _David Radcliffe_, Aug 02 2025