Q: Is 25,365,012 a Fibonacci Number?
A: No, the number 25,365,012 is not a Fibonacci number.
The Fibonacci Sequence is a series of numbers where you add the previous two numbers together. The sum of each is a Fibonacci number.
You start with 0 and add 1 to get the answer 1. You then add 1 + 1 to get 2. Then 2 + 1 to get 3. Then 2 + 3 to get 5, and so on.
To help you see it a little better, the numbers you add together have been color coded:
0 + 1 = 1
1 + 1 = 2
1 + 2 = 3
2 + 3 = 5
3 + 5 = 8
5 + 8 = 13
What would be the next Fibonacci number? If you answered 21, you're right. Here's how: You add 8 + 13, which equals 21. The sum of each set of numbers is a Fibonacci number. There are an infinite number of Fibonacci numbers.
So now that we have a little background on what a Fibonacci number is, let's work through it and try to see if 25,365,012 is a Fibonacci number.
Remember, we start with 0 + 1 = 1 then 1 + 1 = 2 then 1 + 2 = 3 then 2 + 3 = 5, and so on...
Long Form Fibonacci Test
Notice the last equation above (in red). This shows that 25,365,012 is NOT a Fibonacci number because the sum of the last equation is larger than the number 25,365,012 and the sum of the equation before it is smaller than the number 25,365,012.
Here are the next few Fibonacci numbers for you to take a look at:
39,088,169 63,245,986 102,334,155 165,580,141 267,914,296 433,494,437Let's take a look and see...
| Number | 25,365,010 | 25,365,011 | 25,365,013 | 25,365,014 |
| Fibonacci? | no | no | no | no |