for loop in FreeBSD (pfSense) doesn't work

I've just noticed that the same code for for loop in bash doesn't work in FreeBSD wolf@linux:~$ echo $SHELL /bin/bash wolf@linux:~$ wolf@linux:~$ for i in {1..3}; do echo $i; done 1 2 3 wolf@linux:~$ Is there any alternative for this? [2.5.0-RELEASE][admin@pfSense]/root: echo $SHELL /etc/rc.initial [2.5.0-RELEASE][admin@pfSense]/root: [2.5.0-RELEASE][admin@pfSense]/root: for i in {1..3}; do echo $i; done for: Command not found. i: Undefined variable. [2.5.0-RELEASE][admin@pfSense]/root: