  In this note, we construct explicit bases for spaces of overconvergent
$p$-adic modular forms when $p=2,3$ and study their stability under the Atkin
operator. The resulting extension of the algorithms of Lauder is illustrated
with computations of slope sequences of some $2$-adic eigencurves and the
construction of Chow-Heegner points on elliptic curves via special values of
Rankin triple product L-functions.
