deletable primes
Ray Chandler
rayjchandler at sbcglobal.net
Thu Jan 18 17:39:35 CET 2007
> Phil Carmody recently submitted a(9) through a(13) of A125589.
> I disagree with him starting at a(10) though.
>
> I also have more terms for A125590 but since the ones I found above
> disagree with the recent contribution of Phil Carmody, I will wait
> until someone (Phil or otherwise) checks to make sure my program is
> generating good numbers.
I confirm Joshua's correction and extension of A125589 through a(18) and his extension of A125590 through a(15).
Ray Chandler
Consider the sequence {a(k)}, where:
a(1)=1. a(2) = 2.
For n>=3, a(n) is the smallest positive integer not occurring earlier in
the sequence such that (sum{k=1 to n) a(k)) divides product{j=1 to n}
a(j).
I calculate (by hand and by calculator) the sequence beginning:
1,2,3,6,4,8,12,18,10,...
I am about to submit this sequence, but I am unsure I didn't make an
error.
(I bet I did make an error, because the sequence as written above has no
hits in the OEIS.)
Is this sequence a permutation of the positive integers?
Thanks,
Leroy Quet
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