The second and third rectangular numbers are 6 and 12
There is no such formula. Rectangular numbers are composite numbers and there is no known formula that will generate either composite numbers or prime numbers.
42
101
12
50th or Fiftieth Ordinal numbers are just numbers that identify the order of things: 1st (first), 2nd (second), 3rd (third), 4th (fourth), etc.
Rectangular numbers are a subset of composite numbers. The squares of prime numbers will be composite but not rectangular.
If you assume the shape of a rectangular box, you need to choose three numbers which, when multiplied together, give the volume. Please note that this has infinitely many solutions. You can choose ANY positive numbers for the first and second dimension; only the third will be calculated (as volume, divided by the first and the second number).
Ordinal numbers represent placement. First, second, third and so on.
There is no such formula. Rectangular numbers are composite numbers and there is no known formula that will generate either composite numbers or prime numbers.
The third number is 112, the numbers are 86, 86, 112, 172
Cylinders are circles pulled out into the third dimension and rectangular prisms are rectangles pulled into the third dimension.
So far I know that 120 is a rectangular number
rectangular numbers are numbers just displayed in the shape of a rectangle e.g take the number 6 it can be shown as: ** ** or ****** **
First, Second, Third ... are called Ordinal Numbers.
Their order is switched. For example, in the two numbers 12345 and 13245, the second and third digits are transposed.
Cardinal numbers are one, two, three, four, ... Ordinal numbers are first, second, third, fourth, ...
Rectangular numbers are of the form n(n+1) for n = 1, 2, 3, 4, 5, 6, ... The first few rectangular numbers are: 2, 6, 12, 20, 30, 42, ...