

A086565


Smallest k such that (10^k  1)/9 has n distinct prime divisors. Or a(n)= smallest value of k such that A000042(k) has exactly n distinct prime divisors.


0



1, 2, 3, 9, 8, 6, 15, 12, 18, 45, 24, 32, 54, 30, 42, 64, 102, 72, 108, 154, 60, 84, 96, 140, 126, 200, 120, 204, 308, 168, 192, 280, 180, 210, 240, 252
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OFFSET

0,2


COMMENTS

a(40) = 300; all other subsequent terms are > 322.  Ray Chandler, Apr 23 2017


LINKS

Table of n, a(n) for n=0..35.


PROG

(PARI) a(n) = my(k=1); while(omega((10^k  1)/9) !=n, k++); k; \\ Michel Marcus, Apr 23 2017


CROSSREFS

Cf. A000042, A001221, A002275, A095370.
Sequence in context: A021421 A152812 A246825 * A008291 A261525 A122665
Adjacent sequences: A086562 A086563 A086564 * A086566 A086567 A086568


KEYWORD

more,nonn


AUTHOR

Amarnath Murthy, Aug 31 2003


EXTENSIONS

Corrected and extended by Sascha Kurz, Sep 22 2003
a(12)a(15) from David Wasserman, Mar 28 2005
a(16)a(27) from Donovan Johnson, Nov 17 2008
a(28)a(35) from Ray Chandler, Apr 23 2017


STATUS

approved



