As of this writing, the largest known prime number is 277232917-1. “Not large enough!”, I say. Let’s write a computer program that will print out a larger prime number. No, not a program that will take billions of years to run. It should take only a few minutes. There is a small catch. Hardly worth…… Continue reading Large prime numbers

# Category: Math

## How to draw an elliptical orbit

Maybe you’ve heard of the Milankovitch cycles, one of which involves changes to the eccentricity of the Earth’s orbit, as it is perturbed by other objects in the Solar System. Suppose you want to depict this with a diagram, using a circle, and an ellipse of exaggerated eccentricity. You could just draw any old random…… Continue reading How to draw an elliptical orbit

## A puzzle about a Fibonacci-like sequence

I’m thinking of a mathematical sequence, $latex S$, whose terms are all nonnegative real numbers. It is infinite in both directions. Like the Fibonacci sequence, it satisfies the relation: $latex \displaystyle S_n=S_{n-1}+S_{n-2}$ And we are given: $latex \displaystyle S_0=1$ What is the value of $latex S_1$? Surprisingly, you have enough information to figure it out. Note…… Continue reading A puzzle about a Fibonacci-like sequence

## The Balls and Urns Paradox

Start with an empty urn having an unlimited capacity, and a infinite number of balls, labeled “1”, “2”, “3”, etc. At time T minus 1 second, put balls #1-10 into the urn, then take ball #1 out. At time T minus 1/2 second, put balls #11-20 into the urn, then take ball #2 out. At…… Continue reading The Balls and Urns Paradox