1,6,15,20,?,?,?

• Final Series = 1,6,15,20,29,34,43
  
  It increases by +5, +9 alternatively.
  
  1 +5 = 6
  6 +9 = 15
  15+5 = 20
  20+9 = 29
  29+5 = 34
  34+9 = 43.
  
  In other method,
  
  It have two sequence,
  
  1st seq = 1, 15, ??, ??
  2nd seq = 6, 20, ??
  
  Both the sequence increasing by +14.
  
  Final Series = 1, 6, 15, 20, 29, 34, 43
• 12 years agoHelpfull: Yes(1) No(1)
• In series
  1,6,15,20,?,?,?
  next number will be
  1,6,15,20,15,6,1
  
  first number is 1.
  next 1*6/1= 6
  6*5/2 = 15
  15*4/3 =20
  
  next 20*3/4= 15
  15*2/5 =6
  6*1/6 =1
  
  Increasing the denominator of multiplier by 1 and decreasing numerator of multiplier by 1 starting from 6/1.
  
• 12 years agoHelpfull: Yes(1) No(1)