Question 1137872: What is the smallest 4-digit number in the following sequence?
5, 14, 29, 50, 77, …
Answer by Edwin McCravy(20060) (Show Source):
You can put this solution on YOUR website! What is the smallest 4-digit number in the following sequence?
5, 14, 29, 50, 77, …
They're all 2 more than a multiple of 3, so we subtract 2 from each
3, 12, 27, 48, 75
Divide each by 3
1, 4, 9, 16, 25
That's the perfect squares, so the sequence 5, 14, 29, 50, 77, …
has general term
We set that greater than or equal to 1000
Divide thru by 3
So 19 is the smallest integer for which the
sequence has 4 digits.
So we substitute n=19 in the general term
Edwin
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