A138207 - OEIS

The OEIS is supported by the many generous donors to the OEIS Foundation.

A138207

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

4

510510, 965009045, 30989984674, 1673602584618

(list; graph; refs; listen; history; text; internal format)

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), 235-248. [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