A141295 Largest m<=n such that all k with 1<=k<=m are divisors of n or coprime to n.

1, 2, 3, 4, 5, 3, 7, 5, 5, 3, 11, 7, 13, 3, 5, 5, 17, 3, 19, 5, 5, 3, 23, 8, 9, 3, 5, 5, 29, 3, 31, 5, 5, 3, 9, 7, 37, 3, 5, 5, 41, 3, 43, 5, 5, 3, 47, 8, 13, 3, 5, 5, 53, 3, 9, 5, 5, 3, 59, 7, 61, 3, 5, 5, 9, 3, 67, 5, 5, 3, 71, 9, 73, 3, 5, 5, 13, 3, 79, 5, 5, 3, 83, 7, 9, 3, 5, 5, 89, 3, 13, 5, 5, 3

Offset: 1

Author

Reinhard Zumkeller, Jun 23 2008

Keywords

• nonn

Comments

n mod a(n) = 0 or GCD(n,a(n)) = 1;

a(n) = n iff n=1 or n=4 or n is prime; a(A046022(n))=A046022(n);

a(p^2) = 2*p - 1 for odd primes p.

Links

• R. Zumkeller, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A027750, A038566, A076274.