213524

Appears in sequences

• a(n) = 2^n - binomial(n, floor(n/2)).at n=18A045621
• a(n) = 4^n - binomial(2*n,n).at n=9A068551
• Number of n X 2 0..1 arrays with row sums equal and column sums unequal to adjacent columns.at n=17A202736
• Number of (n+2) X (7+2) 0..3 arrays with every consecutive three elements in every row and column having exactly two distinct values, and in every diagonal and antidiagonal not having exactly two distinct values, and new values 0 upwards introduced in row major order.at n=11A252694
• Number of n-step random walks on a line starting from the origin and returning to it at least once.at n=18A307768