18993

Appears in sequences

• Ordered factorizations with one level of parentheses indexed by prime signatures. A050354(A025487).at n=42A050355
• G.f. A(x) defined by: A(x)^2 consists entirely of integer coefficients between 1 and 2 (A083952); A(x) is the unique power series solution with A(0)=1.at n=25A084202
• T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having directed index change 0,0 0,1 1,0 -1,0 or 0,-2.at n=28A264217
• Number of (1+1) X (n+1) arrays of permutations of 0..n*2+1 with each element having directed index change 0,0 0,1 1,0 -1,0 or 0,-2.at n=7A264218
• G.f. satisfies A(x) = 1 + x*A(x)^2 * (1 + x*A(x)^2)^2.at n=7A367282