Next Number | 29 oct

Kshiteej's Avatar, Join Date: Jul 2009
Contributor
What is the next number in below series

1,3,9,29,71, ?
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Time Starts Now
sameer_havakajoka's Avatar
Skilled contributor
134
Kshiteej's Avatar, Join Date: Jul 2009
Contributor
Quote:
Originally Posted by sameer_havakajoka View Post
134
Nope.
How did you calculated it?
sameer_havakajoka's Avatar
Skilled contributor
184
sameer_havakajoka's Avatar
Skilled contributor
213
xpi0t0s's Avatar, Join Date: Aug 2004
Mentor
141
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Its already more than 24 hours and so new entries would not be counted and any entry before this post if correct wins or else OP wins
Kshiteej's Avatar, Join Date: Jul 2009
Contributor
Consider the difference in sucessive numbers.

3-1 = 2 = 2^2 -2 = (1st prime no )^2 - (1st prime no )
9-3 = 6 = 3^2 -3 = (2nd prime no )^2 - (2nd prime no )
29-9 = 20 = 5^2 -5 = (3rd prime no )^2 - (3rd prime no )
71-29 = 42 = 7^2 -7 = (4th prime no )^2 - (4th prime no )

So the answer is 71 + 11^2 - 11 = 181
shabbir's Avatar, Join Date: Jul 2004
Go4Expert Founder
Just a suggestion. Try to reply faster if you are an OP of the competition.