skip_sequence.py

from openerp import fields, models, api

class test_skip_sequence(models.Model):
    _name = 'ir.sequence'
    _inherit = 'ir.sequence'

    @api.cr_uid
    def skip_sequence(self, cr, uid, ids=None, context=None):
        name = 'Sezionale Vendite'
        step = 3
        
        if context is None:
            context = {}

        seq_ids = self.search(cr, uid, [('name', '=', name)], context)
        
        for seq in self.browse(cr, uid, seq_ids, context=context):
            self.write(cr, uid, seq, {'number_next': seq.number_next_actual + step}, context=context)
        
        return None