by Victor Bryant

Published Sunday March 22 2026

Rodney has a set of small identical rods, which he uses to display numbers in “calculator” style. The “0” requires six rods, the “1” requires two rods, the “2”, “3” and “5” require five each, the “4” requires four, the “6” and “9” require six, the “7” requires three and the “8” requires seven. He recently showed me three numbers, each made by using the whole set. The lowest was a three-figure perfect square, the next was a palindromic prime, and the highest was a four-figure prime with its four different digits increasing from left to right.

What were those three numbers?