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A066418 Numbers n for which phi(n) + anti-phi(n)=n. 3
2, 3, 4, 5, 6, 7, 8, 12, 15, 27, 30, 40, 44, 57, 117, 128, 171, 236, 399, 408, 510, 1623, 3597, 3915, 4616, 4684, 7335, 10197, 10768, 14144, 32768, 39387, 76035, 77097 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Anti-phi(n) (A066452) is the number of numbers coprime to all the anti-divisors of n.

See A066272 for definition of anti-divisor.

LINKS

Table of n, a(n) for n=1..34.

Jon Perry, Anti-phi function [Broken link]

Jon Perry, The Anti-divisor [Cached copy]

Jon Perry, The Anti-divisor: Even More Anti-Divisors [Cached copy]

EXAMPLE

The anti-divisors of 7 are 1, 2, 3 and 5. Therefore of the integer 1-6, only 1 is coprime to 2, 3 and 5, therefore anti-phi(7)=1. phi(7)=6, therefore anti-phi(7)+phi(7)=7

CROSSREFS

Cf. A066416, A066417, A058838, A066241, A066452.

Sequence in context: A321334 A238084 A211202 * A015845 A030702 A305926

Adjacent sequences:  A066415 A066416 A066417 * A066419 A066420 A066421

KEYWORD

nonn,more

AUTHOR

Jon Perry, Dec 28 2001

EXTENSIONS

Edited (Anti-phi function link is broken) by Daniel Forgues, Nov 23 2009

a(21) - a(34) from Nathaniel Johnston, Apr 20 2011

STATUS

approved

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Last modified May 21 15:32 EDT 2019. Contains 323444 sequences. (Running on oeis4.)