scan log

this are logs of a port scan i have recently recieved on one of my
machines. i searched for those ports in all known port databases to me,
but couldnt find anything. why would someone scan that specific range
(observe the precise inrementation) of ports on a linux machine?

Jun 11 22:20:21 mordor scanlogd: From 209.3.31.70:20 to 151.202.106.23
ports 2632, 2633, 2634, 2635, 2636, 2637, 2638, 2639, 2640, ..., flags
??r??u, TOS 00, TTL 60, started at 22:20:13

--
Max Gribov
System Administrator
Knowledge Propulsion Laboratories
www.kplab.com