123970

Appears in sequences

• a(n) = T(4*n,n), where T = Catalan triangle (A008315).at n=6A026005
• Seventh column of Catalan triangle A009766.at n=13A064059
• Triangle T(n,k) read by rows: (1/n) * C(2n+k,k-1) * C(n,k); n, k >= 1.at n=40A102537
• Triangle read by rows: T(n,k) is the number of Grand Dyck paths of semilength n that cross downwards the x-axis k times. (A Grand Dyck path of semilength n is a path in the half-plane x>=0, starting at (0,0), ending at (2n,0) and consisting of steps u=(1,1) and d=(1,-1)).at n=45A118919
• a(n) = gcd(Catalan(n), n!).at n=39A170829
• Triangle read by rows: the reversed x = 1+q Narayana triangle at m=2.at n=40A243662
• Number of North-East lattice paths from (0,0) to (n,n) that cross the diagonal y = x horizontally exactly three times.at n=6A268446
• Numbers k such that (26*10^k - 89) / 9 is prime.at n=24A278426