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 A227645 #5 Jul 19 2013 06:04:06 %S A227645 4,8,9,16,27,32,125,128,169,243,361,729,961,1444,10201,403225,725904 %N A227645 Perfect powers equal to the sum of 4 factorial numbers. %C A227645 a(18), if it exists, is larger than 10^100. %H A227645 Giovanni Resta, <a href="/A227645/a227645.txt">Decompositions of a(1)-a(17)</a> %e A227645 729 = 3^6 = 1! + 2! + 3! + 6!. %Y A227645 Cf. A114377, A227644-A227651, A082920. %K A227645 nonn %O A227645 1,1 %A A227645 _Giovanni Resta_, Jul 19 2013