If 3 is the first number & 8 is the 2nd number...
- Thread starter turfqueen
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Another hint:
If you're not interested in writing an explicit formula for any given n (i.e., you only desire to find the two numbers that come immediately before 8 in the list), then you could forget about the numbers 3, 4, 5, 6, and 7, and start instead at the bottom of the list (20), thinking about what you would need to do in terms of arithmetic to go from number to number up the list toward 8.
If you can figure that out, then keep on truck'n ...
Of course, number patterns like the one in Denis' hint are much more interesting. Here's another.
3*3 - 1 = 8
4*3 - 1 = 11
5*3 - 1 = 14
Cheers,
~ Mark
If you're not interested in writing an explicit formula for any given n (i.e., you only desire to find the two numbers that come immediately before 8 in the list), then you could forget about the numbers 3, 4, 5, 6, and 7, and start instead at the bottom of the list (20), thinking about what you would need to do in terms of arithmetic to go from number to number up the list toward 8.
If you can figure that out, then keep on truck'n ...
Of course, number patterns like the one in Denis' hint are much more interesting. Here's another.
3*3 - 1 = 8
4*3 - 1 = 11
5*3 - 1 = 14
Cheers,
~ Mark