COPY with default values won't work?

I'm trying to copy data into the following table:

CREATE SEQUENCE seq_account_type_ndx;

CREATE TABLE accounts (
Account_Type_NDX int4 not null default
nextval('seq_account_type_ndx'),
Account_Name Text
);

Using this as a datafile:
\N|Box
\N|NetSurfer120
\N|eMailer
\N|eMailerLite

I've tried writing the code in C using libpq, using the copy command as the
postgres super user, or using \copy as my normal user. NONE will work with
the "not null" in there, and if I remove it, it just inserts a null value
into account_type_ndx, without using the default. I've also tried
switching the default to a number (ie default 12) instead of the nextval of
the sequence, with no better luck.

Here is the copy command I tend to use:
COPY accounts from stdin USING delimiters '|'
or \COPY accounts from '/tmp/datafile.txt' USING delimiters '|'

Any ideas?