Template:Sequence of the Day for December 3

Intended for: December 3, 2011

Timetable

• First draft entered by Alonso del Arte on November 29, 2011 (based on a remark from Franz Vrabec) ✓
• Draft to be reviewed by October 3, 2011
• Draft to be approved by November 3, 2011

Yesterday's SOTD * Tomorrow's SOTD

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A076512 /A109395:

ϕ (n ) n = ∏ ω (n) i  = 1 (1  −  1 pi   )

, where

ω (n)

is the number of distinct prime factors function.

{1, 1 2  , 2 3  , 1 2  , 4 5  , 1 3  , 6 7  , 1 2  , ⋯}

The denominator is

pω (n)

(the greatest prime factor) if and only if for every

j < ω (n)

, there is a

k < ω (n)

such that

pj ∣ (  pk  −  1)

.