A069549 Smallest composite k such that phi(k) > k*(1-1/n).

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

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: A192030 A117879 A334009 * A118069 A089539 A324010

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