print heights of blocks with out-of-order timestamps

block-times.py

#!/usr/bin/env python3
# When two cosecutive blocks have out of order timestamps (the higher height's time
# is less than the lower height's time), print the height of the lower-height block.
#
# prerequisite;
# $ pip3 install python-bitcoinrpc
# or see https://github.com/jgarzik/python-bitcoinrpc

from bitcoinrpc.authproxy import AuthServiceProxy
api = AuthServiceProxy("http://lmr:lmr@127.0.0.1:8332")

info = api.getblockchaininfo()
tip_height = info['blocks']

prev_time = 0
for height in range(tip_height, 0, -1):
    blockhash = api.getblockhash(height)
    b = api.getblock(blockhash, 1)
    block_time = b['time']
    if prev_time > 0 and block_time > prev_time:
        print(b['height'])
    prev_time = block_time