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A087978 a(n) is the first term in a chain of at least n consecutive numbers, each having exactly m = 5 distinct prime factors. 5
2310, 254540, 1042404, 21871365, 129963314, 830692265, 4617927894, 18297409143, 41268813542, 287980277114, 1182325618032, 6455097761454 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..12.

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]

MATHEMATICA

k=1; Do[While[Union[Table[Length[FactorInteger[i]], {i, k, k+n-1}]]!={5}, k++ ]; Print[k], {n, 1, 8}]

CROSSREFS

Cf. A080569[m=3], A064708[m=2], A087977[m=4], A087978[m=5].

Cf. A138206, A138207, A154573. [Donovan Johnson, Jan 15 2009]

Sequence in context: A046303 A046403 A288072 * A261210 A020435 A288798

Adjacent sequences:  A087975 A087976 A087977 * A087979 A087980 A087981

KEYWORD

more,nonn

AUTHOR

Labos Elemer, Sep 26 2003

EXTENSIONS

More terms from Don Reble, Sep 29 2003

4 more terms from Donovan Johnson, Mar 06 2008

a(11)-a(12) from Donovan Johnson, Jan 15 2009

STATUS

approved

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Last modified January 19 19:49 EST 2019. Contains 319309 sequences. (Running on oeis4.)