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 A111994 #13 Mar 17 2017 00:47:17
%S A111994 1,6,33,176,930,4908,25954,137712,733539,3922834,21060099,113481504,
%T A111994 613619332,3328768344,18112655748,98833261600,540705999621,
%U A111994 2965360687518,16299708148901,89784615643728,495545294427558
%N A111994 Sixth convolution of Schroeder's (second problem) numbers A001003(n), n>=0.
%H A111994 Vincenzo Librandi, <a href="/A111994/b111994.txt">Table of n, a(n) for n = 0..200</a>
%F A111994 G.f.: ((1+x-sqrt(1-6*x+x^2))/(4*x))^6.
%F A111994 a(n)= (6/n)*Sum_{k=1,..,n} binomial(n,k)*binomial(n+k+5,k-1).
%F A111994 a(n) = 6*hypergeom([1-n, n+7], [2], -1), n>=1, a(0)=1.
%F A111994 Recurrence: n*(n+6)*a(n) = (7*n^2+30*n+5)*a(n-1) - (7*n^2+12*n-22)*a(n-2) + (n-3)*(n+3)*a(n-3). - _Vaclav Kotesovec_, Oct 18 2012
%F A111994 a(n) ~ 3*sqrt(3*sqrt(2)-4)*(58-41*sqrt(2)) * (3+2*sqrt(2))^(n+6)/(16*sqrt(Pi)*n^(3/2)). - _Vaclav Kotesovec_, Oct 18 2012
%t A111994 CoefficientList[Series[((1+x-Sqrt[1-6*x+x^2])/(4*x))^6, {x, 0, 20}], x] (* _Vaclav Kotesovec_, Oct 18 2012 *)
%o A111994 (PARI) x='x+O('x^50); Vec(((1+x-sqrt(1-6*x+x^2))/(4*x))^6) \\ _G. C. Greubel_, Mar 16 2017
%Y A111994 Cf. Sixth column of convolution triangle A011117.
%K A111994 nonn,easy
%O A111994 0,2
%A A111994 _Wolfdieter Lang_, Sep 12 2005