How to loop with unix timestamp modifier in busybox date (alpine)

alpine_date_loop.sh

#!/bin/sh

# Go back 1 hour for 1000 loops to add data to redis.

# Inspired by:
# * https://unix.stackexchange.com/questions/339938/busybox-date-command-set-time-with-unix-timestamp
# * https://unix.stackexchange.com/questions/22600/how-to-get-3-minutes-future-date
# * https://unix.stackexchange.com/questions/494581/date-command-in-busybox-not-accepting-formatted-input-date

for H in $(seq 1 1000); do
  # Go back in time by one more hour
  TS=$(date -d "@$(( `date +%s` - (3600 * ${H} * 30) ))" +%s);
  # Add some data to redis based on this timestamp.
  redis-cli zadd checkins-${TS}-${TS} ${TS}000 ${TS}000;
done