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 A262395 #13 Sep 22 2015 12:09:45 %S A262395 1,1,0,1,0,1,1,3,2,5,5,13,13,29,32,71,81,177,209,449,538,1148,1415, %T A262395 3002,3736,7862,9930,20877,26648,55756,71767,149860,194507,405332, %U A262395 529708,1101502,1447956,3006750,3974959,8242691,10948355,22673357,30249668,62583402,83831176,173259448,232917913,480970826,648753720 %N A262395 Difference between the numbers of trees on n vertices with an even number and an odd number of leaves. %C A262395 The sequence could be prepended with a(0)=1 and a(1)=-1. However, it is conjectured that for all n>=2, we have a(n)>=0 (cf. MathOverflow link). %H A262395 MathOverflow, <a href="http://mathoverflow.net/questions/218394/counting-trees-according-to-endpoints">Counting trees according to endpoints</a>, 2015. %F A262395 a(n) = A262430(n) - A262431(n). %F A262395 G.f.: x + A(x,-1), where A(x,y) is g.f. for A055290. %Y A262395 Cf. A055290, A055277. %K A262395 nonn %O A262395 2,8 %A A262395 _Max Alekseyev_, Sep 21 2015