partner-contact/base_partner_sequence/data/partner_sequence.xml

<?xml version="1.0"?>
<openerp>
    <data noupdate="1">

	#
	# Sequences for res.partner
	#

    <record model="ir.sequence" id="seq_res_partner_customer">
        <field name="name">Partner code for customers</field>
        <field name="code">res.partner.customer</field>
        <field name="prefix">C/</field>
        <field name="padding">5</field>
    </record>

    <record model="ir.sequence" id="seq_res_partner_vendor">
        <field name="name">Partner code for suppliers</field>
        <field name="code">res.partner.vendor</field>
        <field name="prefix">S/</field>
        <field name="padding">5</field>
    </record>

    </data>
</openerp>