https://www.cnblogs.com/EasonJim/p/8315939.html
#!/bin/bash for((i=1;i<=10;i++)); do echo $(expr $i \* 3 + 1); done
#!/bin/bash for i in $(seq 1 10) do echo $(expr $i \* 3 + 1); done
#!/bin/bash for i in {1..10} do echo $(expr $i \* 3 + 1); done
#!/bin/bash awk 'BEGIN{for(i=1; i<=10; i++) print i}'