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A246470 Start of the least quadruplet of consecutive squarefree numbers each of which has exactly n distinct prime factors. 3
4058471, 91, 3854, 178086, 15469622, 18230787183 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

By "consecutive squarefree numbers" we mean consecutive terms of A005117, not consecutive integers that also happen to be squarefree.

LINKS

Table of n, a(n) for n=1..6.

EXAMPLE

4058471, 4058473, 4058477, and 4058479 are the smallest 4 primes that are also consecutive squarefree numbers (4058472 = 2^3*3*11*15373, 4058474 = 2*7^2*41413, 4058475 = 3*5^2*53*1021, 4058476 = 2^2*19*53401, and 4058478 = 2*3^3*17*4421), so a(1) = 4058471.

91, 93, 94, and 95 are the smallest 4 semiprimes that are also consecutive squarefree numbers, so a(2) = 91.

3854, 3855, 3857, and 3858 is the smallest 4-tuple of consecutive squarefree numbers each of which has exactly 3 prime factors, so a(3) = 3854.

CROSSREFS

Cf. A005117, A242621 (triple version), A246548 (quintuplet version), A246471.

Sequence in context: A104930 A251614 A187599 * A231614 A191346 A307846

Adjacent sequences:  A246467 A246468 A246469 * A246471 A246472 A246473

KEYWORD

nonn

AUTHOR

Hans Havermann, Aug 27 2014

STATUS

approved

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Last modified October 22 01:48 EDT 2021. Contains 348160 sequences. (Running on oeis4.)