A011753 Smallest number beginning with n and having n different prime divisors (which may be repeated).

11, 20, 30, 420, 5460, 60060, 746130, 80059980, 900029130, 10407767370, 1100869379610, 12026713528830, 1300912477633230, 14299762385778870, 1502172599891453490, 160000041334479776430, 17000158733027932351890

Offset

1,1

Links

Table of n, a(n) for n=1..17.

Example

a(1)=11 because it begins with 1 and has one prime divisor. a(5)=5460=2^2*3*5*7*13 has 5 distinct prime divisors.

Crossrefs

Cf. A077522.

Sequence in context: A044054 A044435 A302563 * A120442 A059407 A109376

Adjacent sequences: A011750 A011751 A011752 * A011754 A011755 A011756

Keyword

base,nonn

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Feb 11 2003

Extensions

More terms from Erich Friedman, Aug 08 2005

a(11) was incorrect. Franklin T. Adams-Watters found a smaller candidate, 1102786855170 and asks if this is the true value of a(11). Dec 07 2006

a(11)-a(17) from Donovan Johnson, Sep 03 2008

Status

approved