Template:Sequence of the Day for January 3

Intended for: January 3, 2012

Timetable

• First draft entered by Alonso del Arte on October 30, 2011 ✓
• Draft reviewed by Daniel Forgues on November 6, 2011 ✓
• Draft to be approved by December 3, 2011

Yesterday's SOTD * Tomorrow's SOTD

The line below marks the end of the <noinclude> ... </noinclude> section.

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A000265: Largest odd divisor of

n

.

{ 1, 1, 3, 1, 5, 3, 7, 1, ... }

Obviously

a (n) = 1

only when

n

is a power of 2 and

a (n) = n

only when

n

is an odd noncomposite number. Somewhat less obviously, this is the numerator of

n 2 n  − 1

and the denominator of

2 n  − 1 n

.