1808929

Appears in sequences

• Number of equivalence classes of ballot paths of length n for the string uu.at n=26A274110
• a(0) = 1, a(1) = 0, a(2) = a(3) = 1; thereafter, a(n) = a(n-1) + a(n-2) + a(n-4).at n=28A347493