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Get Full Access to Discrete Mathematics And Its Applications - 7 Edition - Chapter 2.se - Problem 28e
Get Full Access to Discrete Mathematics And Its Applications - 7 Edition - Chapter 2.se - Problem 28e

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# We define the Ulam numbers by setting u1= 1 and u2 = 2. ISBN: 9780073383095 37

## Solution for problem 28E Chapter 2.SE

Discrete Mathematics and Its Applications | 7th Edition

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Problem 28E

We define the Ulam numbers by setting u1= 1 and u2 = 2. Furthermore, after determining whether the integers less than n are Ulam numbers, we set it equal to the next Ulam number if it can be written uniquely as the sum of two different Ulam numbers. Note that u3 = 3, u4 = 4, u5 = 6, and u 6 = 8.

a) Find the first 20 Ulam numbers.

b) Prove that there are infinitely many Ulam numbers.

Step-by-Step Solution:

SOLUTION

Step 1

We have to find the first 20 Ulam numbers.

We have .

Number 5 and 7 are not Ulam numbers because their addition is not distinct.

We have 5 = 1+4 , 2+3 where 1,2,3,4 are Ulam numbers.

And 7 = 3+4, 1+6 where 1,6,3,4 are Ulam numbers.

8 = 6+2 , Ulam number

9 = 3+6 , 1+8  not an Ulam number

10 = 2+8, 4+6 not an Ulam number.

Proceeding like this we have to find the first 20 Ulam numbers.

Step 2 of 3

Step 3 of 3

##### ISBN: 9780073383095

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