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A045934 Numbers n such that n through n+5 have the same number of distinct prime factors. 4
91, 141, 142, 143, 212, 213, 214, 323, 324, 2302, 2303, 6850, 9061, 10280, 10281, 15740, 16130, 16164, 16682, 16683, 19052, 19053, 20212, 20213, 21195, 21196, 21790, 22055, 23064, 25779, 25780, 25991, 28608, 28674, 29971, 31442, 33084 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Amiram Eldar, Table of n, a(n) for n = 1..10000 (terms 1..2620 from Zak Seidov)

Roger B. Eggleton and James A. MacDougall, Consecutive integers with equally many principal divisors, Math. Mag. 81 (2008), 235-248.

EXAMPLE

The numbers from 91 to 96 all have 2 distinct prime factors: 91=7*13, 92=2^2*23, 93=3*31, 94=2*47, 95=5*19, and 96=2^5*3.

MATHEMATICA

Select[Range[35000], Length[Union[Length/@FactorInteger[Range[#, #+5]]]]==1&]  (* Harvey P. Dale, Feb 27 2011 *)

CROSSREFS

Cf. A001221, A006049, A006073, A045932-A045933, A045935-A045938, A088983.

Sequence in context: A020301 A083517 A088983 * A051347 A293647 A225908

Adjacent sequences:  A045931 A045932 A045933 * A045935 A045936 A045937

KEYWORD

nonn

AUTHOR

David W. Wilson

STATUS

approved

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Last modified December 5 06:51 EST 2020. Contains 338944 sequences. (Running on oeis4.)