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 A218559 #10 Jan 04 2013 17:57:17
%S A218559 0,6,714,1047188,30515132780,21936856591278330,
%T A218559 459986443452971306412268,324518550895166392891543292552264,
%U A218559 8727963565271662417355532872177263437534624,9999999999888888888777777776666666555555444443333222110
%N A218559 Sum_{i=0..n-1} i*(n^(i+1)-1)/(n-1)*n^(i(i+1)/2).
%C A218559 Largest number which can be written in base n using d+1 times the digit d, d=0,...,n-1. (Or: such that for each k=1,...,n, some digit is used exactly k times.)
%e A218559 Written in the respective bases, a(2) = 6 = 110[2], a(3) = 714 = 222110[3], a(4) = 1047188 = 33322110[4], etc.
%o A218559 (PARI) a(b)=sum(i=1,b-1,(b^(i+1)-1)\(b-1)*b^(i*(i+1)\2)*i)
%Y A218559 Cf. A218556, A210666, A182040; A167819, A031948.
%K A218559 nonn,base
%O A218559 1,2
%A A218559 _M. F. Hasler_, Nov 02 2012