Q. What is the next number of the following sequence.
4,2,5,9,5,11,13,7,16,17,9,21,...

• sequence goes -2, +3, +4, -4, +6, +2, -6, +9, +1, -8, +12
  There are three diff patterns
  (a) -2, -4, -6, -8
  (b) +3, +6, +9, +12
  (c) +4, +2, +1 ???
  For pattern (c) each leap is the previous leap divided by 2
  Therefore 2 divided by 1 = 0.5 so the next leap is +0.5
  21 + 0.5 = 21.5
  So ANS = 21.5
• 11 years agoHelpfull: Yes(17) No(5)
• 4,2,5,9,5,11,13,7,16,17,9,21...
  take first 3 digits...4,2,5
  '4'-2='2'
  '2'+3='5'
  take next 3 digits... 9,5,11
  '9'-4='5'
  '5'+6='11'....
  take next 3 digits... 13,7,16
  '13'-6='7'
  '7'+9 ='16'
  take next 3 digits... 17,9,21
  '17'-8='9'
  '9'+12='21'
  BUT we cant say the next 3 digits, unless one digit is given
• 11 years agoHelpfull: Yes(8) No(4)
• Seperate the given nos as set of 3 each as follows,
  4, 2, 5 9, 5, 11 13, 7, 16 , 17, 9, 21 , ?
  First no 1st set + 5 gives first no of second set as follows,
  4+5=9
  Similarly, 2+3=5, 5+6=11
  From next series onwards use the no. by 1 less than the no. Added for the previous seris
  I.e instead of using 5, 3, 6 use 4, 2, 5
  Now u will get the following series
  9+4=13, 5+2=7, 11+5=16
  13+4=17, 7+2=9, 16+5=21
  17+4=21, 9+2=11, 21+5=26
  The new series is 21, 11, 26
  
  
• 10 years agoHelpfull: Yes(4) No(0)
• arrange in 3 parts(4,2,5)(9,5,11)etc
  4-(+2)-- 2 5
  9---(+4)--- 5 11
  13---(+6)--- 7 16
  17---(+8)--- 9 21
  21----(+10)----11
• 10 years agoHelpfull: Yes(0) No(0)