  For g $\ge$ 0, let n g denote the number of numerical semi-groups of genus g.
A conjecture by Maria Bras-Amor\'os in 2008 states that the inequality n g
$\ge$ n g--1 + n g--2 should hold for all g $\ge$ 2. Here we show that such an
inequality holds for the very large subtree of numerical semigroups satisfying
c $\le$ 3m, where c and m are the conductor and multiplicity, respectively. Our
proof is given in the more flexible setting of gapsets, i.e. complements in N
of numerical semigroups.
