files / problems / erdos-szekeres-seven / compute / verify_record.py
#!/usr/bin/env python3
"""Replay the explicit published ES(7) interval from its two formulas."""
from math import comb
def main() -> None:
k = 7
lower = 2 ** (k - 2) + 1
upper = comb(2 * k - 5, k - 2) - comb(2 * k - 8, k - 3) + 2
assert lower == 33
assert upper == 113
print(f"record arithmetic: {lower} <= ES(7) <= {upper}")
if __name__ == "__main__":
main()