[seqfan] Policy on near-duplicates

[N. J. A. Sloane]

If there are 2 sequences in the OEIS which are different
but closely related (for example, one might be obtained
by adding 1 to every term of the other), then we keep both,
but provide cross-references.

The main reason is that (obviously) there are two schools
of though about which is the best version.

Also my preference is to keep a sequence once it is in the OEIS,
unless it is wrong.

Neil