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 A147842 #28 Feb 19 2020 19:30:47
%S A147842 45,540,50040,3364890,334795890,27671338200,2761284321300,
%T A147842 241066406350560,24071550717893160,2164109364980520560,
%U A147842 216167870783354294560,19804111510101766391920,1978598460245429017365520,183672136030518949796846320
%N A147842 Sum of all balanced numbers less than 10^n.
%C A147842 See reference for definition of balanced number.
%C A147842 Partial sums of A147808. Up to n=3, equal to the sum of palindromes A002113 < 10^n; then it differs from this sequence by the sum of terms < 10^n in A145808. - _M. F. Hasler_, Nov 23 2008
%H A147842 Wei Zhou, <a href="/A147842/b147842.txt">Table of n, a(n) for n = 1..46</a>
%H A147842 Project Euler, <a href="http://projecteuler.net/index.php?section=problems&id=217">Problem 217: Balanced Numbers</a>
%F A147842 a(n) = Sum_{k=1..n} A147808(k). - _M. F. Hasler_, Nov 23 2008
%o A147842 (PARI) s=0; A147842 = vector(13,k,s+=A147808(k)) \\ _M. F. Hasler_, Nov 23 2008
%K A147842 nonn,base
%O A147842 1,1
%A A147842 Alexis Olson (AlexisOlson(AT)gmail.com), Nov 14 2008
%E A147842 a(9)-a(12) from _M. F. Hasler_, Nov 23 2008
%E A147842 a(13)-a(46) added by _Wei Zhou_, Oct 10 2011