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 A071107 #2 Feb 27 2009 03:00:00
%S A071107 1,3,27,
%T A071107 115792089237316195423570985008687907853269984665640564039457584007913129639936
%N A071107 a(n) is the greatest integer that can be obtained from the integers {1, 2, 3, ..., n} using each number at most once and the operators +,-,*,/,^.
%C A071107 a(4) = 2^(4^4) = 2^256 = 115792089237316195423570985008687907853269984665640564039457584007913129639936 with 78 digits. a(5) = 2^(3^(4^6)) with more than 10^1950 digits.
%e A071107 a(3) = 27 because 3^(2+1) = 27 is the greatest integer that can be obtained by using 1, 2, 3 once and the operations +, -, *, /, ^.
%Y A071107 Cf. A070960.
%K A071107 nonn
%O A071107 1,2
%A A071107 Koksal Karakus (karakusk(AT)hotmail.com), May 27 2002