[seqfan] Comment in A095810

David Corneth davidacorneth at gmail.com
Mon Oct 30 17:39:55 CET 2017


Hi all,

There is a comment written in 2004 by Francisco Salinas in A095810
<https://oeis.org/A095810> that might need some more editing I think.
It's
"If we have only the last k digits of a large integer N, you find that N is
not a power of 2 if and only if the number given by those digits is
divisible by 5 OR not a multiple of 2^k OR a value > 2^k*(5^k-1)."

I think it would mean that 6 is a power of 2; it's a multiple of 2 and not
divisible by 5 (The last test doesn't change the verdict as 10^k has k+1
digits. 10^k - 2^k < N < 10^k isn't divisible by 2^k hence is excluded by
the first test.).

So, what to do with the comment?

Best,
David

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