seq has the same seq command as ubuntu 18.04
env GOPATH=`pwd` go get -u github.com/guonaihong/coreutils/seq/seq
Usage of seq:
-f, --format string
use printf style floating-point FORMAT
-s, --separator string
use STRING to separate numbers (default: \n)
-w, --equal-width string
equalize width by padding with leading zeroes
seq -f "%a" 100
seq -f "%A" 100