2020656

Appears in sequences

• Number of 2 up, 2 down, 2 up, ... permutations of length 2n + 1.at n=6A005981
• The 2-Up sequence: formed from final entries in rows of A058257.at n=13A058258
• 2 up, 2 down, ..., 2 up, 2 down permutations of length 4n+1.at n=3A131453