Where's 209.240.157.34 ?

Got a spam advertising a web page there, ARIN claims it's not allocated
although all the space around it is. It routes through Tierranet.

Do they often lose allocations?

Regards,
John Levine, johnl@iecc.com, Primary Perpetrator of "The Internet for Dummies",
Information Superhighwayman wanna-be, http://iecc.com/johnl, Sewer Commissioner
Finger for PGP key, f'print = 3A 5B D0 3F D9 A0 6A A4 2D AC 1E 9E A6 36 A3 47