The feature number applies to verbforms which have the vf-m-values ind, sub, impr and cond, and this, in combination with the p-values 1, 2 et 3, for the specified tns-values. This feature doesn't apply to infinitive and present participle verbforms. Concerning past participle forms, the feature n applies in combination with the feature g. Notice that for imperative forms (vf-m-value impr), restrictions concerning the combination of p- and n-values exist: If the p-value is 1, the n-value must be p. The p-value 2 can be combined with the two n-values, s and p.
It can occur that for some defective verbs all n-values are not realized.