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NUMBER SEQUENCES PROBLEMS Try to guess the next number in each sequence using the simplest mathematical operations or ideas

1• 8723, 3872, 2387, ..........

2• 1, 4, 9, 18, 35, .............

3• 23, 45, 89, 177, .............

4• 7, 5, 8, 4, 9, 3, ..............

5• 3, 8, 15, 24, 35, .............

6• 2, 4, 5, 10, 12, 24, 27, .............

7• 1, 3, 4, 7, 11, 18, ..............

8• 99, 92, 86, 81, 77,..............

9• 0, 4, 2, 6, 4, 8, ..............

10• 1, 2, 6, 24, 120, ..............

11• 5, 7, 12, 19, 31, 50, ..................

12• 27, 82, 41, 124, 62, 31, 94, 47, 142, 71, 214, 107,...............

13• 126, 63, 190, 95, 286, 143, 430, 215, 646, 323, 970, ...............

14• 4, 7, 15, 29, 59, 117, ..............

15• 4, 4, 341, 6, 4, 4, 6, 6, 4, 4, 6, 10, 4, 4, 14, 6, 4, 4, 6, 6, 4, 4, 6, 22, 4, 4, 9. 6 ...............

 Feb 27, 2015

Best Answer 

 #6
avatar+130071 
+5

7•  1, 3, 4, 7, 11, 18, ..............This is the Lucas Series - L(n) -  for n = 1,2,3,4........

This can also be generated by  the Fibonacci Series  where L(n) = Fib(n + 1) + Fib(n - 1) for n = ≥ 1

8•     99, 92, 86, 81, 77,.............. the next number is 74  .....

10•   1, 2, 6, 24, 120.............. = n!

11•    5, 7, 12, 19, 31, 50, ..................  the next number is 81...... The pattern is L(n) + F(n+1) for n ≥ 2

14•    4, 7, 15, 29, 59, 117, ..............the next number is 235.......the pattern is twice the first number minus 1.....and then twice this result plus 1.....and this dual pattern repeats.....

 

 

             

 Feb 27, 2015
 #1
avatar+26396 
+5

1• 8723, 3872, 2387, ..........

$$8723, 3872, 2387, \textcolor[rgb]{1,0,0}{7238}$$

 Feb 27, 2015
 #2
avatar+118690 
+5

2•       1, 4, 9, 18, 35, 68.......                $$T_n=2^n+n-2$$

 Feb 27, 2015
 #3
avatar+26396 
+5

3• 23, 45, 89, 177, .............

$$23, 45, 89, 177, \textcolor[rgb]{1,0,0}{353} \qquad T_n = 2^{n-1}\cdot 22 +1 \quad n = 1,2, \cdots$$

 Feb 27, 2015
 #4
avatar+26396 
+5

4• 7, 5, 8, 4, 9, 3, ..............

$$\textcolor[rgb]{1,0,0}{7}, 5, \textcolor[rgb]{1,0,0}{8}, 4, \textcolor[rgb]{1,0,0}{9}, 3, \textcolor[rgb]{1,0,0}{10}$$

 Feb 27, 2015
 #5
avatar+26396 
+5

5• 3, 8, 15, 24, 35, .............

$$3, 8, 15, 24, 35, \textcolor[rgb]{1,0,0}{48} \qquad T_n = n\cdot(n+2) \quad n=1,2, \cdots$$

 Feb 27, 2015
 #6
avatar+130071 
+5
Best Answer

7•  1, 3, 4, 7, 11, 18, ..............This is the Lucas Series - L(n) -  for n = 1,2,3,4........

This can also be generated by  the Fibonacci Series  where L(n) = Fib(n + 1) + Fib(n - 1) for n = ≥ 1

8•     99, 92, 86, 81, 77,.............. the next number is 74  .....

10•   1, 2, 6, 24, 120.............. = n!

11•    5, 7, 12, 19, 31, 50, ..................  the next number is 81...... The pattern is L(n) + F(n+1) for n ≥ 2

14•    4, 7, 15, 29, 59, 117, ..............the next number is 235.......the pattern is twice the first number minus 1.....and then twice this result plus 1.....and this dual pattern repeats.....

 

 

             

CPhill Feb 27, 2015

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