What is the next number in this sequence? (There are no hidden cubes.)
How many corners does a hypercube (a 4-dimensional cube) have?
How many line-segments are there in the 4th image of this growing tree sequence?
What is the sum of the first 13 positive odd numbers?
The sizes of the first 9 squares that make this spiral are:
How big is the 10th square added to the spiral?