[seqfan] Re: guessing doubling formulas for sequences

franktaw at netscape.net franktaw at netscape.net
Wed Mar 11 00:11:21 CET 2009

Note that, in order to actually be able to compute the
sequence, you need a formula for a(2n+1) as well as
the formula for a(2n).

A number of sequences related to binary numbers
have formulas of this type:

A001511: a(2n) = a(n) + 1, a(2n+1) = 1
A000120: a(2n) = a(n), a(2n+1) = a(n)  + 1
A000265: a(2n) = a(n), a(2n+1) = 2n + 1
A002416=A080791: a(2n) = a(n) + 1, a(2n+1) = a(n)

Franklin T. Adams-Watters

-----Original Message-----
From: Georgi Guninski <guninski at guninski.com>

by ``doubling formula'' i mean given $n$ an near neighbors
$a_n,a_{n+1}...a_{n+k}$ compute a_{2 n}


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