445962870

Appears in sequences

• a(n) = number of (s(0), s(1), ..., s(n)) such that s(i) is a nonnegative integer and |s(i) - s(i-1)| = 1 for i = 1,2,...,n and s(0) = 2. Also a(n) = sum of numbers in row n+1 of array T defined in A026009.at n=30A026010
• a(n) = binomial(2*n,n) - binomial(2*n-2,n-1); or (3n-2)*C(n-1), where C = Catalan numbers (A000108).at n=15A051924
• Number of ways to select 15 knights from n knights sitting at a round table if no adjacent knights are chosen.at n=16A188225
• a(n) is the number of ballot sequences of length n tied or won by at most 2 votes.at n=30A337499
• a(n) is the number of ballot sequences of length n tied or won by at most 3 votes.at n=30A337500