A132788 - OEIS

%I #9 Mar 08 2025 12:27:01

%S 1,2,7,24,79,258,851,2852,9715,33582,117561,416012,1485787,5348866,

%T 19389675,70715324,259289563,955277382,3534526361,13128240820,

%U 48932534019,182965127258,686119227277,2579808294624,9723892802879,36734706144278,139067101831981

%N a(n) = 2*binomial(2*n,n)/(n+1) - n.

%H Andrew Howroyd, <a href="/A132788/b132788.txt">Table of n, a(n) for n = 1..200</a>

%F a(n) = 2*A000108(n) - n. - _Andrew Howroyd_, Aug 10 2018

%e a(4) = 24 = sum of row 4 terms of triangle A132787: (1 + 11 + 11 + 1).

%t Table[2Binomial[2n,n]/(n+1)-n,{n,27}] (* _James C. McMahon_, Mar 08 2025 *)

%o (PARI) a(n) = 2*binomial(2*n,n)/(n+1) - n; \\ _Andrew Howroyd_, Aug 10 2018

%Y Row sums of A132787.

%Y Cf. A000108 (Catalan numbers).

%K nonn,changed

%O 1,2

%A _Gary W. Adamson_, Aug 30 2007

%E Name changed, a(8) corrected and a(11)-a(27) from _Andrew Howroyd_, Aug 10 2018