for i in range(3):
    for num in range(0, 496, 5):
        if i == 1:
            requests.get('https://my-website.com?from={}&to={}'.format(num, num + 5))

        # ............
        # separate conditions for 2 other urls in this case :(

urls = [<url1>, <url2>,....<url50>] # maybe each url has placeholders

for url in urls:
    # do some magic