A086286 Smallest prime factor of 7-smooth numbers.

1, 2, 3, 2, 5, 2, 7, 2, 3, 2, 2, 2, 3, 2, 2, 2, 3, 2, 5, 3, 2, 2, 2, 5, 2, 2, 2, 3, 2, 7, 2, 2, 2, 2, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 2, 3, 2, 2, 2, 5, 2, 2, 3, 2, 2, 3, 2, 2, 2, 2, 5, 2, 3, 2, 2, 2, 2, 2, 2, 3, 2, 3, 5, 2, 2, 2, 2, 2, 2, 2, 2, 3, 2, 2, 2, 7, 2, 2, 3, 2, 2, 2, 2, 3, 2, 2, 3, 2, 2

Offset: 1

Author

Reinhard Zumkeller, Jul 15 2003

Keywords

• nonn

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A002473, A020639, A086287.

Formula

a(n) = A020639(A002473(n));

a(n) <= A086287(n) <= 7.