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 A161323 #7 Jul 08 2019 13:35:00 %S A161323 6,34,760,17700,177770000,77777600000,1777777000000, %T A161323 177777777770000000000,17777777777777777777700000000000000000000, %U A161323 77777777777777777777777777777600000000000000000000000000000 %N A161323 Perfect numbers written in base 8. %C A161323 All members end in 0, 1, 4, 5, or 6. Conjecturally, apart from the first two terms, all terms end in 0. %H A161323 Harvey P. Dale, <a href="/A161323/b161323.txt">Table of n, a(n) for n = 1..15</a> %t A161323 FromDigits[IntegerDigits[#,8]]&/@PerfectNumber[Range[10]] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 08 2019 *) %Y A161323 Cf. A000396, A135650, A160962. %K A161323 nonn,base %O A161323 1,1 %A A161323 _Juri-Stepan Gerasimov_, Jun 07 2009 %E A161323 Edited by _Charles R Greathouse IV_, Mar 19 2010