2731365

Appears in sequences

• Number of aperiodic necklaces of n beads of 2 colors, 11 of them black.at n=19A032169
• Number of necklaces with 11 black beads and n-11 white beads.at n=20A032196
• a(n) = lcm(1,2,...,2*n) / (n*binomial(2*n, n)).at n=29A068553
• a(n) = binomial(prime(n),n)/prime(n) where prime(n) = n-th prime.at n=10A075872
• 9th column of Catalan triangle A009766.at n=13A124087
• Number of admissible sequences of order j; related to 7x+1 problem.at n=10A174796
• Number of North-East lattice paths from (0,0) to (n,n) that cross the diagonal y = x horizontally exactly three times.at n=8A268446
• a(n) = (15*n)!*(2*n)!/((10*n)!*(6*n)!*n!).at n=2A295462
• a(n) = binomial(A007310(n+1),n+1)/A007310(n+1).at n=10A367521