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 A231606 #9 Nov 20 2013 02:02:36
%S A231606 1,3,11,25,137,127,949,2003,7129,7381,83711,86021,1145993,1171733,
%T A231606 1195757,2436559,42142223,41461543,800021557,788381929,799467289,
%U A231606 810048769,18863914247,19087007117,99182995801,100212655201,312536252003,315404588903
%N A231606 Maximal possible numerator for a sum of the form 1 +/- 1/2 +/- 1/3 +/- ... +/- 1/n.
%t A231606 nMax = 19; d = {0}; Table[d = Flatten[{d + 1/n, d - 1/n}]; Max[Abs[Numerator[d]]], {n, nMax}]
%Y A231606 Cf. A003418 (maximal denominator).
%Y A231606 Cf. A061195 (minimal numerator), A232090 (minimal denominator).
%K A231606 nonn
%O A231606 1,2
%A A231606 _T. D. Noe_, Nov 19 2013