Find N th term of the sequence, 1, 2, 4, 7, 11.

Please Friends, Help me in solving the this problem.

• Every term can be written as ( n*(n-1)/2) + (1)
  
• 11 years agoHelpfull: Yes(2) No(0)
• Thank you Mahesh.
  How can we know that every term can be written in that form. Is there any procedure to find it. Please Explain...
• 11 years agoHelpfull: Yes(0) No(0)
• 2-1=1
  4-2=2
  7-4=3
  11-7=4
  and then x-11=5
  so
  x=16
• 11 years agoHelpfull: Yes(0) No(0)