report on recent OEIS activity

[Joseph S. Myers]

On Wed, 25 Feb 2004, N. J. A. Sloane wrote:

> For the conjectured duplicates, I am marking them by
> saying something like:
> 
> %Y A059975 Is this the same as A087656? - Ralf Stephan, Feb 21, 2004

They are the same (with relative offset 1, i.e. A087656(n+1) =
A059975(n)).  If p is the least prime factor of n then the rule of A087656
goes (n+1)/1 -> (n+2)/2 -> ... -> (n+p)/p = (n/p + 1)/1 so A087656(n+1) =
A087656(n/p + 1) + (p-1), and clearly A059975(n) = A059975(n/p) + (p-1),
and the most natural start for the induction is A059975(1) = A087656(2) =
0 (one place before the currently listed sequences start).

Another apparent cause of duplication I've observed is that it seems that
the first submitter of a sequence submits a short sequence, then the
second calculates a longer sequence, (I suppose) searches but doesn't find
it because they searched for more terms than were in the already present
sequence, and submits the longer sequence as new.  In a case I recently
reported (A032511 = A036900), the sequence names are even textually
identical (something that seems dubious even for different sequences, as
the name should be a meaningful if concise definition of the sequence that
distinguishes it from all others).

-- 
Joseph S. Myers
jsm at polyomino.org.uk