Over a million developers have joined DZone.
Platinum Partner

Narcissus Prime in Python

· Web Dev Zone

The Web Dev Zone is brought to you in partnership with Mendix. Download this Forrester Report to gain a better understanding of the low-code platform market and how to make a strategic platform selection you won’t regret.

I’ve been looking back on some of my blog posts that included Mathematica code to see whether I could rewrite them using Python. For example, I rewrote my code for finding sonnet primes in Python a few days ago. Next I wanted to try testing the Narcissus prime.

Futility closet describes the Narcissus prime as follows:

Repeat the string 1808010808 1560 times, and tack on a 1 the end. The resulting 15601-digit number is prime, and because it’s a palindrome made up of the digits 1, 8, and 0, it remains prime when read backward, upside down, or in a mirror.

My Mathematica code for verifying this claim is posted here. Here’s Python code to do the same thing:

    from sympy.ntheory import isprime
    isprime(int("1808010808"*1560 + "1"))

This does indeed return True. However, the Mathematica code ran for about 2 minutes and the SymPy code took 17.5 hours, about 500 times longer.

The Web Dev Zone is brought to you in partnership with Mendix. Better understand the aPaaS landscape and how the right platform can accelerate your software delivery cadence and capacity with the Gartner 2015 Magic Quadrant for Enterprise Application Platform as a Service.

Topics:

Published at DZone with permission of John Cook , DZone MVB .

Opinions expressed by DZone contributors are their own.

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}