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 A162214 #15 Nov 04 2017 15:56:34 %S A162214 1,2,6,12,30,60,126,248,504,1020,2046,4092,8190,16380,32760,65520, %T A162214 131070,262134,524286,1048560,2097144,4194300,8388606,16777200, %U A162214 33554425,67108860,134217702,268435440,536870910,1073741820,2147483646,4294967264,8589934584 %N A162214 a(n) = the largest positive multiple of n with exactly n digits when written in binary. %H A162214 Alois P. Heinz, <a href="/A162214/b162214.txt">Table of n, a(n) for n = 1..1000</a> %F A162214 a(n) = n * floor((2^n-1)/n). - _Alois P. Heinz_, Jul 11 2009 %p A162214 a:= n-> n*floor((2^n-1)/n): seq(a(n), n=1..40); # _Alois P. Heinz_, Jul 11 2009 %t A162214 Array[# Floor[(2^# - 1)/#] &, 31] (* _Michael De Vlieger_, Nov 04 2017 *) %Y A162214 Cf. A162213. %K A162214 base,nonn %O A162214 1,2 %A A162214 _Leroy Quet_, Jun 28 2009 %E A162214 More terms from _Alois P. Heinz_, Jul 11 2009