Today’s question is from Venkatesh.

Give the fascinating story behind this picture and the relation to the book.

Quoting Dinesh, the first visual is the Ulam spiral discovered by mathematician Stanislaw Ulam that reveals surprising and as yet not completely understood patterns in prime number spirals. A couple of years before the discovery of the spiral, Arthur C. Clarke described a very similar idea in his novel “The city and the stars”. Read more about this here.

Prime Spiral or the Ulam Spiral, a plot of positive integers in a spiral and then marking the prime numbers along the spiral.The circled primes tend to fall in a strange diagonal line.

Arthur Clarke in his book ‘City and the Stars’ described this phenomenon predating Ulam’s discovery by severeal years.

I remember asking this question in an intra college quiz some 5 years ago, and it flew well over the top of everyone’s heads.

Anyway, the concept of an Ulam Spiral was vaguely suggested in Clarke’s novel where the central character loves playing around with numbers and finding patterns.

Picture:- Stanislaw Ulam’s prime number spiral.

Answer, pre-Google:-

May be the prime number spiral forms the basis of this book.

Answer, post-Google:-

“Although Stanislaw Ulam is generally credited with the discovery of the Prime Number Spiral, it appears that Ulam might not have been the first person to make this discovery. Chapter 6 of Arthur C. Clarke’s classic 1956 novel “The City and the Stars” opens with the hero Jeserac analysing a “whirlpool” of integers on his computer monitor and seeing the primes strung out “across its surface as beads might be arranged at the intersections of a mesh”. It looks as though Arthur C. Clarke had already discovered the Prime Number Spiral seven years before it was found by Ulam. “

Fractals ?

1. Ulam Spiral (discovered by Stainslaw Ulam in 19644)

2. Arthur C. Clarke described the prime spiral (Ulam Spiral) in his novel The City and the Stars (1956)

– Apurva

The first visual is the Ulam spiral discovered by mathematician Stanislaw Ulam that reveals surprising and as yet not completely understood patterns in prime number spirals. A couple of years before the discovery of the spiral, Arthur C. Clarke described a very similar idea in his novel “The city and the stars”.