2,10,26,50.......
87 th no in the series

• 2,10,26,50......
  (1^2+1),(3^2+1),(5^2+1),(7^2+1),....
  
  Tn = (2n-1)^2+1
  
  T87 = (2*87 -1)^2 + 1 = (173^2+1) = 29930
  
• 10 years agoHelpfull: Yes(57) No(3)
• sorry mine is wrong
• 10 years agoHelpfull: Yes(4) No(1)
• here
  a=2
  d=(n-1)*8 [means difference is 1*8, 2*8, 3*8 , etc...]
  
  87th term= a+(n-1)d+(n-1)d
  = a+2(n-1)d
  =2+2(87-1)8
  =2+2*86*8
  =1378
• 10 years agoHelpfull: Yes(1) No(17)
• 1^2 +1=2
  3^2+1+10
  5^2+1=26
  now 87th odd no. Tn=a+(n-1)d
  1+(87-1)2
  = 173
  therefore; 173^2 +1=29930
  
• 10 years agoHelpfull: Yes(1) No(0)