Find the missing term : 1,6,15, ? ,45,66,91

• answer is 28
  1+5=6
  6+ (5+4)=15
  15+(9+4)=28
  28+(13+4)=45
  45+(17+4)=66
  66+(21+4)=91.
• 10 years agoHelpfull: Yes(1) No(1)
• ans:28. for 1st no. 1=1*1, for 2nd 6=2*3, for 3rd 15=3*5, for 4th 28=4*7, for 5th 5*9, for 6th 66=6*11, for 7th 91=7*13. It is the product of consecutive natural numbers with the consecutive odd natural numbers
• 10 years agoHelpfull: Yes(1) No(0)