# [Python 2], 42 bytes <!-- language-all: lang-python --> f=lambda k,n=0:n*(max(`n`)<'2')or f(k,n+k) [Try it online!][TIO-k70axfj2] [Python 2]: https://docs.python.org/2/ [TIO-k70axfj2]: https://tio.run/##JYxBCoMwEADvfcXezDZ7SHJqpL6kCEY0dkldJXior48BbzMMzH4e301cKbH7hXWcAiSSzrTyVGv4q0EGfDeuwS1DVDXphCVWYWCBHGSZlSOP@kZryL5Qf6wnV9GYvn0A7JnlAKZ6YCwX "Python 2 – Try It Online" --- Full program, same length: a=b=input() while'1'<max(`b`):b+=a print b [Try it online!][TIO-k70b26pi] [Python 2]: https://docs.python.org/2/ [TIO-k70b26pi]: https://tio.run/##K6gsycjPM/r/P9E2yTYzr6C0REOTqzwjMydV3VDdJjexQiMhKUHTKknbNpGroCgzr0Qh6f9/YwA "Python 2 – Try It Online"