Sequence & Its Numerators & Denominators
Leroy Quet
qqquet at mindspring.com
Wed Feb 26 04:10:21 CET 2003
I just submitted this to sci.math. I already sent the m=1 example to
seq.fan a little while back. Perhaps someone could calculate the
numerator/denominator sequences for the first couple of m's and post them
to the EIS.
Thanks,
Leroy Quet
---------------
This is a generalization of the sequence discussed at:
http://mathforum.org/discuss/sci.math/t/482979
Given a fixed positive integer m;
Let a[1] = any nonzero rational where its denominator is relatively
prime to m.
Let:
1
a[k+1] = a[k] + ------------- , for all positive integers k.
m + 1 /a[k]
In linear mode:
a[k+1] = a[k] + 1/(m + 1 /a[k]) , for all positive integers k.
If n[k] = numerator of a[k] in reduced form,
and d[k] = denominator of a[k] in reduced form,
then, for k = all positive integers,
n[k+2] =
n[k+1]*(m*n[k+1] + n[k+1]^2/(2n[k]^2) -m^2 *n[k]^2/2),
and d[k+2] =
d[k+1]*(d[k+1] + d[k+1]^2/d[k]^2 -d[k]^2)
The above are from these recursions:
n[k+1] = n[k] *(m*n[k] + 2*d[k]),
d[k+1] = d[k] *(m*n[k] + d[k])
Noteworthy facts:
*d[2] involves m. But the recursion, for d[k+2] in terms of d[k] and
d[k+1], itself is independent of m.
*Each d[k+1] is divisible by d[k], and each n[k+1] is divisible by
n[k].
*(d[k+1]/d[k]) is relatively prime to (n[j+1]/n[j]) for every positive
integer k and every positive integer j.
Thanks,
Leroy Quet
More information about the SeqFan
mailing list