Keith number

Question

Is it possible to make a program in java to check whether the entered number is keith number or not without using array?

A n digit number x is called Keith number if it appears in a special sequence (defined below) generated using its digits. The special sequence has first n terms as digits of x and other terms are recursively evaluated as sum of previous n terms.

Input : x = 197
Output : Yes
197 has 3 digits, so n = 3
The number is Keith because it appears in the special sequence that has first three terms as 1, 9, 7 and remaining terms evaluated using sum of previous 3 terms. 1, 9, 7, 17, 33, 57, 107, 197, .....
Input : x = 12
Output : No
The number is not Keith because it doesn't appear in the special sequence generated using its digits. 1, 2, 3, 5, 8, 13, 21, .....
Input : x = 14
Output : Yes
14 is a Keith number since it appears in the sequence, 1, 4, 5, 9, 14, ...

Answer 1

https://code.sololearn.com/cKeCv3X81Cf5/?ref=app

I used int for the sum and String to store the needed numbers.

Answer 2

https://code.sololearn.com/czuhko71uZF4/?ref=app
Using strings

Answer 3

Hi! Can you mention what a keith number is? It is possible to solve anything in programming. so don't worry, your question has an answer

Answer 4

Denise Roẞberg

Thanks...

😁😁

Answer 5

I would say the trick is to remove the first number if you have the sum.
197:

1 + 9 + 7 = 17
9 + 7 + 17 = 33
7 + 17 + 33 = 57
17 + 33 + 57 = 107
33 + 57 + 107 = 197

If sum = input --> keith number

If sum > input --> not a keith number

It is like a fibonacci sequence.