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 A006679 M1978 #40 Jan 10 2018 16:11:11
%S A006679 0,1,2,10,83,946,13772,244315,5113208,123342166,3369568817,
%T A006679 102831001120,3467225430308,128006254663561,5135734326127862,
%U A006679 222498607683528550,10352141336173618883,514815201125079097006,27251316075035460318032,1529842445683171428183355
%N A006679 Number of planted binary phylogenetic trees with n labels.
%D A006679 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006679 Gheorghe Coserea, <a href="/A006679/b006679.txt">Table of n, a(n) for n = 0..200</a>
%H A006679 L. R. Foulds, R. W. Robinson, <a href="http://dx.doi.org/10.1007/BFb0091819">Enumeration of binary phylogenetic trees</a> Combinatorial mathematics, VIII (Geelong, 1980), pp. 187-202, Lecture Notes in Math., 884, Springer, Berlin-New York, 1981. Math. Rev. 83a:05071.
%H A006679 L. R. Foulds and R. W. Robinson, <a href="/A006677/a006677.pdf">Enumeration of binary phylogenetic trees</a>, pp. 187-202, Lecture Notes in Math., 884, Springer, Berlin-New York, 1981. (Annotated scanned copy)
%H A006679 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>
%H A006679 <a href="/index/Tra#trees">Index entries for sequences related to trees</a>
%F A006679 E.g.f: (1 - (1 + 2*exp(x) - 2*exp(x)^2)^(1/2))/exp(x). - _Gheorghe Coserea_, Aug 04 2015
%F A006679 a(n) = Sum_{j=0..n} C(n,j)*(-1)^(n-j)* Sum_{k=1..j} 2^(1-k)*(2*k-2)!/ (k-1)!* Sum_{i=0..j} stirling2(i,k)*k^(j-i)*C(j,i). - _Vladimir Kruchinin_, Nov 17 2015
%F A006679 a(n) ~ sqrt(3-sqrt(3)) * n^(n-1) / (log((1+sqrt(3))/2)^(n-1/2) * exp(n)). - _Vaclav Kotesovec_, Nov 29 2015
%t A006679 CoefficientList[Series[(1 - Sqrt[1 + 2*E^x - 2*E^(2*x)])/E^x, {x, 0, 20}], x] * Range[0, 20]! (* _Vaclav Kotesovec_, Nov 29 2015 *)
%o A006679 (PARI) x='x+O('x^33); Vec(serlaplace((1 - (1 + 2*exp(x) - 2*exp(x)^2)^(1/2))/exp(x))) \\ _Gheorghe Coserea_, Aug 04 2015
%o A006679 (Maxima)
%o A006679 a(n):=sum(((sum((2^(1-k)*(2*k-2)!/(k-1)!*sum((stirling2(i,k)*k^(j-i))*binomial(j,i),i,0,j)),k,1,j))*(-1)^(n-j))*binomial(n,j),j,0,n); /* _Vladimir Kruchinin_, Nov 17 2015 */
%K A006679 nonn
%O A006679 0,3
%A A006679 _N. J. A. Sloane_, _Simon Plouffe_
%E A006679 More terms from _Gheorghe Coserea_, Aug 04 2015