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 A119856 #24 May 23 2018 16:41:13
%S A119856 1,1,3,9,37,168,895,5097,30983,196096,1283552,8621364,59176966,
%T A119856 413613891,2936303012,21128390679,153841228779,1131941424480,
%U A119856 8406680733066,62958726953945,475074493277317,3609405128045162,27593870865196624,212159118489924538,1639760091688265416
%N A119856 Number of equicolorable (unrooted) trees on 2n nodes.
%C A119856 For precise definition, recurrence and asymptotics see the Pippenger reference.
%H A119856 Andrew Howroyd, <a href="/A119856/b119856.txt">Table of n, a(n) for n = 1..100</a>
%H A119856 Austin Mohr, <a href="http://austinmohr.com/home/?page_id=1422">Unlabeled Trees</a>
%H A119856 N. Pippenger, <a href="http://dx.doi.org/10.1137/S0895480100368463">Enumeration of equicolorable trees</a>, SIAM J. Discrete Math., 14 (2001), 93-115.
%F A119856 a(n) = (A000081(n) + A119857(n))/2. - _Andrew Howroyd_, May 21 2018
%o A119856 (PARI) \\ R is b.g.f of rooted trees x nodes, y in one part
%o A119856 R(n)={my(A=O(x)); for(j=1, 2*n, A = if(j%2,1,y)*x*exp(sum(i=1, j, 1/i * subst(subst(A + x * O(x^(j\i)), x, x^i), y, y^i)))); A};
%o A119856 seq(n)={my(A=Pol(R(n))); my(r(x,y)=substvec(A, ['x,'y], [x,y/x])); Vec(polcoeff((r(x,y/x) + r(y/x,x) - r(x,y/x)*r(y/x,x)), 0) + O(y*y^n) + r(y,y))/2} \\ _Andrew Howroyd_, May 23 2018
%Y A119856 Cf. A000081, A119855, A119857.
%K A119856 nonn
%O A119856 1,3
%A A119856 _N. J. A. Sloane_, Aug 04 2006
%E A119856 a(8)-a(9) from _John P. McSorley_, Aug 08 2017
%E A119856 Terms a(10) and beyond from _Andrew Howroyd_, May 21 2018