This site can be very useful with this sort of problem.
The On-Line Encyclopedia of Integer Sequences
This is something I should have learned in high school, but I never quite got it.
Write down explicit formulate for the following sequences:
1, 4, 36, 576, 14400, 518400 ...........
For this, I squared rooted the numbers.. so I'm trying to find the pattern between:
1, 2, 6, 24, 120, ...... but I can't find it. Is there a systematic approach to find the nth term for such a sequence? Obviously the arithmetic and geometric formulas won't work. But is there another logical way?
And secondly, find the nth term of:
3, 9, 18, 30, 48, 66, 87 ..........
Now, again, I can see some sort of pattern. 9-3 = 6, 18-9 = 9, 30-18 = 12, =15, =18 etc. But I can't apply this.
Please help. Thanks.
This site can be very useful with this sort of problem.
The On-Line Encyclopedia of Integer Sequences
Hello, WWTL@WHL!
The second one is baffling . . .
Find the nth term of: .3, 9, 18, 30, 48, 66, 87, . . .
We have: .3(1), 3(3), 3(6), 3(10), 3(16), 3(22), 2(29) , . . .
We seem to have: 3 times a Triangular Number: .
. . but the fifth term breaks the pattern.
The 5th, 6th and 7th terms seem to be: .3 × (a Triangular Number plus 1)
. . So what's going on?