Robtex

Up: 13.33.75.0/24
Can't show all results, try to descend to a more specific CIDR
Down left: 13.33.75.0/26
Down right: 13.33.75.64/26
(Some of the IP numbers are capped at 3 entries)

IP	Type	Hostname
13.33.75.4	A+PTR	server-13-33-75-4.ewr52.r.cloudfront.net
13.33.75.20	PTR	server-13-33-75-20.ewr52.r.cloudfront.net
13.33.75.32	A+PTR	server-13-33-75-32.ewr52.r.cloudfront.net
13.33.75.37	PTR	server-13-33-75-37.ewr52.r.cloudfront.net
13.33.75.39	A	bsmtechhq.slack.com
13.33.75.39	A	careem22.slack.com
13.33.75.39	A	boylesoftware.slack.com
13.33.75.60	PTR	server-13-33-75-60.ewr52.r.cloudfront.net
13.33.75.78	A+PTR	server-13-33-75-78.ewr52.r.cloudfront.net