diff --git a/semaphoreci/semaphore-runner.sh b/semaphoreci/semaphore-runner.sh
index 2bf8ce0d52..177fe77cda 100755
--- a/semaphoreci/semaphore-runner.sh
+++ b/semaphoreci/semaphore-runner.sh
@@ -17,7 +17,7 @@ PHASES=(${@:-SETUP RUN})
 create_container() {
     # create autopkgtest LXC image; this sometimes fails with "Unable to fetch
     # GPG key from keyserver", so retry a few times
-    for retry in $(seq 5); do
+    for retry in {1..5}; do
         sudo lxc-create -n $CONTAINER -t download -- -d $DISTRO -r $RELEASE -a $ARCH --keyserver hkp://keyserver.ubuntu.com:80 && break
         sleep $((retry*retry))
     done