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 A146028 #21 May 03 2019 08:40:14 %S A146028 0,1,2,3,4,5,6,7,15,16,174731235562130,174731235562131, %T A146028 174731235562132,174731235562143,174731235562147,174731235562170, %U A146028 174731235562171,174731235564710,174731235564711,174731236371006,25354527232277132536350,25354527232277132536351 %N A146028 Numbers that can be written from base 2 to base 15 using only the digits 0 to 7. %C A146028 It is a plausible conjecture that there are no more terms, but this has not been proved. - _N. J. A. Sloane_, Nov 17 2017 %H A146028 Stuart A. Burrell, Han Yu, <a href="https://arxiv.org/abs/1905.00832">Digit expansions of numbers in different bases</a>, arXiv:1905.00832 [math.NT], 2019. %t A146028 Select[Range[0, 10^5], Function[n, Times @@ Boole@ Map[Max@ IntegerDigits[n, #] <= 7 &, Range[2, 15]] > 0]] (* _Michael De Vlieger_, Aug 15 2016 *) %Y A146028 Cf. A146025, A146026, A146027, A146029, A131646, A275600. %K A146028 nonn,base %O A146028 1,3 %A A146028 _Daniel Mondot_, Nov 02 2008, Nov 06 2008