

A138207


a(n) is the first term in a chain of at least n consecutive numbers each with exactly 7 distinct prime factors.


4




OFFSET

1,1


COMMENTS

a(5) > 10^13.


LINKS

Table of n, a(n) for n=1..4.
Roger B. Eggleton and James A. MacDougall, Consecutive integers with equally many principal divisors, Math. Mag. 81 (2008), 235248. [T. D. Noe, Oct 13 2008]


CROSSREFS

Cf. A087977, A087978, A138206, A154573.
Sequence in context: A147574 A046325 A136352 * A249881 A205291 A205899
Adjacent sequences: A138204 A138205 A138206 * A138208 A138209 A138210


KEYWORD

nonn,more


AUTHOR

Donovan Johnson, Mar 06 2008


EXTENSIONS

a(4) from Donovan Johnson, Jan 15 2009


STATUS

approved



