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 A132788 #9 Mar 08 2025 12:27:01
%S A132788 1,2,7,24,79,258,851,2852,9715,33582,117561,416012,1485787,5348866,
%T A132788 19389675,70715324,259289563,955277382,3534526361,13128240820,
%U A132788 48932534019,182965127258,686119227277,2579808294624,9723892802879,36734706144278,139067101831981
%N A132788 a(n) = 2*binomial(2*n,n)/(n+1) - n.
%H A132788 Andrew Howroyd, <a href="/A132788/b132788.txt">Table of n, a(n) for n = 1..200</a>
%F A132788 a(n) = 2*A000108(n) - n. - _Andrew Howroyd_, Aug 10 2018
%e A132788 a(4) = 24 = sum of row 4 terms of triangle A132787: (1 + 11 + 11 + 1).
%t A132788 Table[2Binomial[2n,n]/(n+1)-n,{n,27}] (* _James C. McMahon_, Mar 08 2025 *)
%o A132788 (PARI) a(n) = 2*binomial(2*n,n)/(n+1) - n; \\ _Andrew Howroyd_, Aug 10 2018
%Y A132788 Row sums of A132787.
%Y A132788 Cf. A000108 (Catalan numbers).
%K A132788 nonn
%O A132788 1,2
%A A132788 _Gary W. Adamson_, Aug 30 2007
%E A132788 Name changed, a(8) corrected and a(11)-a(27) from _Andrew Howroyd_, Aug 10 2018