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Mystery sequence (Posted on 2022-10-13) Difficulty: 4 of 5
16, 128, 384, 512, 1024, 1536, 1792, 2176, 2560, 2912, ?, ...

No Solution Yet Submitted by Math Man    
Rating: 5.0000 (1 votes)

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Solution? | Comment 1 of 8
Many of the powers of 2 are there.  Observe they all contain the digit 1: 16, 128, 512, 1024.  If this is true then 2^13=8192 is the next power of 2 in the sequence.

384 = 2^7*3 and contains a 3
1536 = 2^9*3 and contains a 3
1792 = 2^8*7 and contains a 7
2176 = 2^7*17 and contains the digit string 17
2560 = 2^9*5 and contains a 5
2912 = 2^5*7*13 but 7*13=91

So it looks like the sequence is just odd numbers times a power of 2 that contain themselves.  

For k odd, if k*2^n contains the digit string of k then it's in the list.

My guess is the next number in the sequence is 3072 = 3*2^10 but I didn't check all the numbers in between. 



  Posted by Jer on 2022-10-13 09:02:50
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