

A079482


Smallest number k such that k and k+1 have n and n+1 distinct prime divisors.


1



1, 5, 65, 1364, 40754, 1774409, 58524465, 5327923964, 555409903685, 70367042561529, 5819629108725509, 567969628457303709
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..11.


EXAMPLE

a(3) = 1364 because 1364 has 3 and 1365 has 4 distinct prime divisors.


MATHEMATICA

a[n_] := Module[{k = 1}, While[PrimeNu[k] != n  PrimeNu[k + 1] != n + 1, k++]; k]; Array[a, 10, 0] (* Amiram Eldar, Dec 03 2018 *)


PROG

(PARI) for(n=1, 10, k=1; while(omega(k)!=n  omega(k+1)!=n+1, k++); print1(k", "))


CROSSREFS

Cf. A001221.
Sequence in context: A121822 A056245 A195886 * A147625 A157097 A234295
Adjacent sequences: A079479 A079480 A079481 * A079483 A079484 A079485


KEYWORD

more,nonn


AUTHOR

Jason Earls, Jan 16 2003


EXTENSIONS

a(6) from Ryan Propper, Jul 21 2006
a(7)a(8) from Donovan Johnson, Apr 05 2008
a(9)a(11) from Donovan Johnson, Feb 04 2009
a(0)=1 preprended by Rémy Sigrist, Dec 03 2018


STATUS

approved



