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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

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Last modified January 16 03:30 EST 2019. Contains 319184 sequences. (Running on oeis4.)