[seqfan] Re: Mystery tour with a(n)=sigma(a(n-1))

Richard Mathar mathar at strw.leidenuniv.nl
Sat Feb 20 14:40:11 CET 2010

This is an open call to compute a file a115350.txt for the outcome
of the n -> sigma(n)-n map, following the standard b-file rules but
replacing -1 for unknown values. To give an idea of the format see
http://www.strw.leidenuniv.nl/~mathar/progs/a115350.txt .

The last line is a comment showing the "quality" of the file by counting
the -1's in the n-range.
This would allow to derive relationships and sequences like A127163, A127164 etc
more easily by scanning a115350.txt .

Richard Mathar

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