80738domain: NAppears in sequencesa(1)=1; a(n+1) = Sum_{k=1 to n} a(k) a(ceiling(n/k)).at n=13A097919The number of triangles in an equipotential triangle divided by medians into n rows of smaller triangles.at n=21A210687p-INVERT of (0,1,0,1,0,1,...), where p(S) = 1 - S^3 - S^6.at n=23A291221