http://olddomain.com/
http://olddomain.com/45
http://olddomain.com/p/93

http://newdomain.com/
http://newdomain.com/45
http://newdomain.com/p/93

RewriteEngine on

RewriteCond %{REQUEST_URI}
RewriteRule  http://newdomain.com/

RewriteCond %{REQUEST_URI} (d+)/
RewriteRule (d+)/ http://newdomain.com/$1

RewriteCond %{REQUEST_URI} p/(d+)/
RewriteRule p/(d+)/ http://newdomain.com/p/$1

RewriteEngine On
RewriteRule ^(.*) http://newdomain.com/$1 [R=301]

RewriteEngine On
RewriteRule ^/(45|p/93|$)$ http://newdomain.com/$1 [R,L]