108 56 29 15 8 x
Find x?

• tetranacci numbers are a generalization of the Fibonacci numbers defined by T_0=0, T_1=1, T_2=1, T_3=2, and the recurrence relation
  
  Answer is 4 :
  T_n=T_(n-1)+T_(n-2)+T_(n-3)+T_(n-4)
  
  for n>=4. They represent the n=4 case of the Fibonacci n-step numbers. The first few terms for n=0, 1, ... are 0, 1, 1, 2, 4, 8, 15, 29, 56, 108, 208, ...
• 10 years agoHelpfull: Yes(28) No(11)
• 108-56=52 now 52=27*2-2
  56-29=27 now 27=14*2-1
  29-15=14 now 14=7*2-0
  15-8=7 now 7=(8-x)*2-(-1)
  8-x=(8-x) so, 7=16-2x+1
  2x=17-7=10
  x=5 ans.
  
• 10 years agoHelpfull: Yes(16) No(1)
• x is 4
  first one is 108
  2nd is (108+4)/2=56
  3rd is (56+2)/2=29
  4th is (29+1)/2=15
  5th is (15+1)/2=8
  6th will be (8+0)/2=4
• 10 years agoHelpfull: Yes(9) No(11)
• It is a generalization of the fibonacci sequence knows as the tetranacci sequence. It is similar to the fibonacci sequence where each subsequent number is the sum of the previous two. With a tetranacci sequence each subsequent number is the sum of the previous four, so the full sequence looks like this: 0, 0, 0, 1, 1, 2, 4, 8, 15, 29, 56, 108, 208, 401. This sequence can be very hard if you have no idea were to look, therefore learn to recognise these types of sequences.
• 10 years agoHelpfull: Yes(2) No(1)
• 
  tetranacci numbers are a generalization of the Fibonacci numbers defined by T_0=0, T_1=1, T_2=1, T_3=2, and the recurrence relation
  
  Answer is 4 :
  T_n=T_(n-1)+T_(n-2)+T_(n-3)+T_(n-4)
  
  for n>=4. They represent the n=4 case of the Fibonacci n-step numbers. The first few terms for n=0, 1, ... are 0, 1, 1, 2, 4, 8, 15, 29, 56, 108, 208, ...
• 9 years agoHelpfull: Yes(2) No(0)
• (108/2)+2=56
  (56/2)+1=29
  (29/2)i.e 14+1=15
  (15/2)i.e 7+1=8
  (8/2)+2=6
  Ans:-6
  
• 10 years agoHelpfull: Yes(1) No(10)
• 108-56=52 now 52=27*2-2
  56-29=27 now 27=14*2-1
  29-15=14 now 14=7*2-0
  15-8=7 now 7=(8-x)*2-(-1)
  8-x=(8-x) so, 7=16-2x+1
  2x=17-7=10
  x=2 ans.
• 10 years agoHelpfull: Yes(1) No(3)
• ans is 4
  4
  4*2-0=8 (first we subtract 0)
  8*2-1=15 ( next we subtract 1)
  15*2-1=29 (now we subract sum of 0+1=1 ie sum of previous values we subtracted)
  15*2-1=29 (now we subtract 0+1=1 from the product term)
  29*2-2=56 (now we subtract 0+1+1=2 i.e sum of all previous nos we subtracted)
  56*2-4=108 ( here again we subtract sum of all previous nos we subtracted ( i.e 0+1+1+2=4) from the product term)
  that means the first no should be 4,so answer is 4
• 10 years agoHelpfull: Yes(1) No(4)
• This might be right answer , just check before you conclude :
  
  8*2 = 16 - 1 = 15
  15*2 = 30 - 1 = 29
  29*2 = 58 - 2 = 56
  56*2 =112 - 4 = 108
  
  here the logic is for odd numbers [ -1 ],for even numbers[ - starts with 2 if any even numbers follows then - (multiples of 2) ]
  
  hence answer is 5 * 2 = 10 - 2 = 8 .
• 10 years agoHelpfull: Yes(1) No(2)
• can any 1 tell the correct answer
• 10 years agoHelpfull: Yes(1) No(1)
• it is following Fibonacci series..... 0,1,1,2,4,8,16........
  56+56=112-4=108
  29+29=58-2=56
  15+15=30-1=29
  8+8=16-1=15
  4+4=8-0=8
  so the ans is.........4
• 9 years agoHelpfull: Yes(1) No(0)
• plzz check the ques. i think the 2nd no. should be 66.
  then the ans will be 1.
• 10 years agoHelpfull: Yes(0) No(6)
• answer is 5
  5,8,15,29,56,108
  
  
• 10 years agoHelpfull: Yes(0) No(2)
• ans is 5
  108/2=54 ,54+2
  56/2=28,28+1
  29/2=14, 14+1
  8/2=4,4+1=5
• 10 years agoHelpfull: Yes(0) No(2)