Generating the ssh Keygen to login to server without password prompt

Hostname:/home/username/.ssh > ssh-keygen
Generating public/private rsa key pair.
Enter file in which to save the key (/home/username/.ssh/id_rsa):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /home/username/.ssh/id_rsa.
Your public key has been saved in /home/username/.ssh/id_rsa.pub.
The key fingerprint is:
7f:21:a4:57:fd:ce:13:a6:8b:0e:d5:2c:17:33:18:e6 username@Hostname
The key's randomart image is:
+--[ RSA 2048]----+
|           o     |
|          o o.   |
|          .E.+.  |
|         o .o +. |
|        S oo.+ o.|
|         o..o.oo.|
|         .. .. .o|
|          ... . .|
|          .o .   |
+-----------------+

Hostname:/home/username/.ssh >

Hostname:/home/username/.ssh > ls -lart
total 152
-rw-r--r--    1 username  staff         61537 Aug 25 08:42 known_hosts
drwxr-xr-x    4 username  staff          4096 Aug 26 10:54 ..
-rw-r--r--    1 username  staff           395 Aug 26 12:38 id_rsa.pub
-rw-------    1 username  staff          1675 Aug 26 12:38 id_rsa
drwx------    2 username  staff           256 Aug 26 12:38 .

Hostname:/home/username/.ssh > cat -n id_rsa.pub
     1  ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDMjTKlVGLSRpPBAdGZs07Go6XifBHVMBBZNxortPv9MQibR9xHZU5LguzN+dFgpSY58nxbozmE7eMYqJryaaecLxluzkY3uCYdQljVF/oWm0TvoYlzwScji8BIXKyqORjMHfjbHcIQgT5EPAup0IdCIihEwohsZ3Ur7elKfvOwPYm8+UPrfJrba7lBl6KQ50u5ssHznj7kXuzIWU2HrTVn1q+/Jjr3iXEcdQro6olOfvBifBHxfhImZezGHOsmVdzCwX08SzLBgCgvOwedTbgSzu8/iA/1mp8dnoVzCaOZ2511cT4TI2K052PXi6MSMRrgEwiMhOE2uE2APRvrxS7/ username@Hostname

Hostname:/home/username/.ssh >
Hostname:/home/username/.ssh > scp -p id_rsa.pub username@newhostname:/home/username/.ssh/authorized_keys
username@newhostname password:
id_rsa.pub                                                                                                                 100%  395     0.4KB/s   00:00

Hostname:/home/username/.ssh >
Hostname:/home/username/.ssh > cd

Hostname:/home/username > ssh newhostname
Last login: Fri Aug 26 12:42:03 WET 2011 on ssh from Hostname
*******************************************************************************
*                                                                             *
*  AIX Version 6.1                                                            *
*                                                                             *
*  - setup network and routes                                                 *
*  - modify /etc/snmpdv3.conf                                                 *
*  - modify /etc/motd                                                         *
*  - install sdd driver if SAN used                                           *
*                                                                             *
*******************************************************************************

newhostname:/home/username > exit
Connection to newhostname closed.

Hostname:/home/username >