216638domain: NAppears in sequencesG.f. satisfies A(x) = 1 + x / (1 - x*A(x)^2)^2.at n=10A367236Antidiagonal sums of A369326.at n=13A369328Irregular triangle read by rows: T(n,k) is the number of flattened Catalan words of length n with exactly k symmetric peaks, with k >= 0.at n=49A372883