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find the next number in the series

 
Myke Enriq
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Which one of the numbers in the series is wrong, and should be replaced?
2 - 4 - 8 - 16 - 20 - 22 - 44 - 46
 
Paul Clapham
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20.

It should be 32.

The sequence is 2^n mod 42.
 
fred rosenberger
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Paul Clapham wrote:20.

It should be 32.

The sequence is 2^n mod 42.

Then how can 46 be valid?
 
Paul Clapham
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Umm... good question. 46 is still congruent to 256 mod 42, though.
 
Seetharaman Venkatasamy
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past 4 hours I am thinking of this... no luck till now... let me try further ;)
 
Matthew Brown
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Change to 16 to 10. I'll leave the justification for now, but it's not a very complicated sequence.
 
Paul Clapham
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Oh yeah, it's A099942. Pity, I was kind of attached to my "42" idea.
 
Seetharaman Venkatasamy
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Matthew Brown wrote:Change to 16 to 10.

Hmm then I can tell the solution...
+2 next *2 => then next element is 92...
 
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