320892

Appears in sequences

• Co-growth function of a certain group.at n=5A007986
• a(n) = A026615(2*n, n).at n=10A026616
• a(n) = A026615(n, floor(n/2)).at n=20A026621
• a(n) = binomial(2*n+2,n) - 2*binomial(2*n,n) + binomial(2*n-2,n).at n=10A262768