More on "numbral" divisors
John Layman
layman at calvin.math.vt.edu
Tue Dec 18 19:11:31 CET 2001
On Dec 12, 2001, Marc LeBrun (mlb at mail.well.com) conjectured that
the number of proper "numbral" divisors of 2^n-1 gives A048888,
later confirmed by Richard Schroeppel (rcs at cs.arizona.edu).
Calculations that I have made recently suggest the following possibly
related conjecture concerning A007059 (balanced ordered trees with
n nodes).
Conjecture: For n>=1, A007059(n+1) is the number of "numbral" divisors
of (4^n-1)/3 = A002450(n).
Can anyone confirm this?
Further, I have shown that A002450(n) = (4^n-1)/3 is the nth umbral
power of 5.
More information about the SeqFan
mailing list