#!/usr/bin/env python3 def nth_code(n): code = 20151125 for i in range(n): code = code * 252533 % 33554393 return code def code_index(row, col): left = col - 1 right = row - 1 left_bottom = col * left // 2 right_top = row * right // 2 - right return row * col + left_bottom + right_top - 1 print(nth_code(code_index(3010, 3019)))