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 A131430 #5 Sep 01 2018 21:28:40
%S A131430 1,2,7,25,88,311,1114,4050,14917,55528,208459,787920,2994655,11433998,
%T A131430 43824437,168520201,649840740,2512011359,9731179138,37768570827,
%U A131430 146833956266,571711568905,2229035221824,8701426599353,34005503702176,133030452858279,520905732440782
%N A131430 Row sums of triangle A131429.
%H A131430 Andrew Howroyd, <a href="/A131430/b131430.txt">Table of n, a(n) for n = 0..200</a>
%F A131430 a(n) = binomial(2*n, n) - (n+1) + Sum_{k=0..n} binomial(2*k, k)/(k+1). - _Andrew Howroyd_, Aug 28 2018
%e A131430 a(3) = 25 = sum of row 3 terms of triangle A131429: (5 + 5 + 6 + 9).
%o A131430 (PARI) a(n)={binomial(2*n,n) - n - 1 + sum(k=0, n, binomial(2*k,k)/(k+1))} \\ _Andrew Howroyd_, Aug 28 2018
%Y A131430 Cf. A000108, A131427, A131428, A131429.
%K A131430 nonn
%O A131430 0,2
%A A131430 _Gary W. Adamson_, Jul 10 2007
%E A131430 Terms a(10) and beyond from _Andrew Howroyd_, Aug 28 2018