What you're asking can be accomplished with
hping3 -S -p 80 192.168.23.42
-S tells the command to send TCP SYN packets, so that each packet is a new connection attempt and doesn't get dismissed as "unrelated to an existing TCP connection."
-p 80 tells the command to connect to port 80 on the remote host (192.168.23.42, replace the address with your actual host).
You can add
-i NUM to wait NUM seconds between each packet.