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A069549 Smallest composite k such that phi(k) > k*(1-1/n). 2
4, 4, 9, 25, 25, 49, 49, 121, 121, 121, 121, 169, 169, 289, 289, 289, 289, 361, 361, 529, 529, 529, 529, 841, 841, 841, 841, 841, 841, 961, 961, 1369, 1369, 1369, 1369, 1369, 1369, 1681, 1681, 1681, 1681, 1849, 1849, 2209, 2209, 2209, 2209, 2809, 2809, 2809 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Or, least composite k such that k is coprime to the n-1 numbers k+1 ... k+n-1. E.g. a(4) = 25 because 25 is coprime to 26, 27 and 28. - Amarnath Murthy, Apr 20 2004

LINKS

Table of n, a(n) for n=1..50.

FORMULA

a(n)=nextprime(n)^2=A007918(n)^2

CROSSREFS

Cf. A052349.

Sequence in context: A112683 A192030 A117879 * A118069 A089539 A117416

Adjacent sequences:  A069546 A069547 A069548 * A069550 A069551 A069552

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre, Apr 21 2002

EXTENSIONS

Edited by David Wasserman, Apr 23 2007

STATUS

approved

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Last modified December 11 19:09 EST 2017. Contains 295919 sequences.