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 A006078 M3822 #39 Feb 18 2019 12:59:31
%S A006078 1,1,5,12,45,143,511,1768,6330,22610,81818,297160,1086813,3991995,
%T A006078 14733435,54587280,203000094,757398510,2834519142,10637507400,
%U A006078 40023665682,150946230006,570534682710,2160865067312,8199711750100
%N A006078 Number of triangulated (n+2)-gons rooted at an exterior edge.
%D A006078 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%D A006078 P. K. Stockmeyer, The charm bracelet problem and its applications, pp. 339-349 of Graphs and Combinatorics (Washington, Jun 1973), Ed. by R. A. Bari and F. Harary. Lect. Notes Math., Vol. 406. Springer-Verlag, 1974.
%H A006078 Vincenzo Librandi, <a href="/A006078/b006078.txt">Table of n, a(n) for n = 2..1000</a>
%H A006078 S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, <a href="http://dx.doi.org/10.1021/ci00026a012">Enumeration of polyene hydrocarbons: a complete mathematical solution</a>, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751.
%H A006078 S. J. Cyvin, J. Brunvoll, E. Brendsdal, B. N. Cyvin and E. K. Lloyd, <a href="/A002057/a002057.pdf">Enumeration of polyene hydrocarbons: a complete mathematical solution</a>, J. Chem. Inf. Comput. Sci., 35 (1995) 743-751. [Annotated scanned copy]
%H A006078 P. J. Stockmeyer, <a href="/A006078/a006078.pdf">The charm bracelet problem and its applications</a>, pp. 339-349 of Graphs and Combinatorics (Washington, Jun 1973), Ed. by R. A. Bari and F. Harary. Lect. Notes Math., Vol. 406. Springer-Verlag, 1974. [Scanned annotated and corrected copy]
%F A006078 Stockmeyer gives a g.f.
%F A006078 G.f.: (4*(1-x-x^2)-(1-2*x)(1-4*x)^(1/2)-3(1-4*x^2)^(1/2))/(8*x^2). - _Emeric Deutsch_, Dec 19 2004
%F A006078 a(n) ~ 2^(2*n-1) / (sqrt(Pi)*n^(3/2)). - _Vaclav Kotesovec_, Mar 06 2014
%p A006078 G:=(4*(1-x-x^2)-(1-2*x)*(1-4*x)^(1/2)-3*(1-4*x^2)^(1/2))/8/x^2: Gser:=series(G,x=0,35): seq(coeff(Gser,x^n),n=2..28); # _Emeric Deutsch_, Dec 19 2004
%t A006078 g:=(4*(1-x-x^2)-(1-2*x)*(1-4*x)^(1/2)-3*(1-4*x^2)^(1/2))/8/x^2; gser := Series[g, {x, 0, 26}]; Drop[ CoefficientList[gser, x], 2] (* _Jean-François Alcover_, Apr 06 2012, after _Emeric Deutsch_ *)
%t A006078 Drop[CoefficientList[Series[(4(1-x-x^2)- (1-2x)Sqrt[1-4x]- 3Sqrt[1- 4x^2])/(8x^2),{x,0,30}],x],2] (* _Harvey P. Dale_, Apr 07 2013 *)
%K A006078 nonn,easy,nice
%O A006078 2,3
%A A006078 _N. J. A. Sloane_, E. K. Lloyd (E.K.Lloyd(AT)soton.ac.uk)
%E A006078 More terms from _Emeric Deutsch_, Dec 19 2004