470051domain: NAppears in sequencesa(n) = a(n-1) + Sum_{k=0..n-3} a(k) for n >= 2, a(0)=1, a(1)=2.at n=24A049853Number of positive words of length n in the monoid Br_3 of positive braids on 4 strands.at n=15A097550Number of tatami tilings of an 8 X n grid (with monomers allowed).at n=19A192094