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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
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 (5-tuple version), A246471.
Sequence in context: A104930 A251614 A187599 * A231614 A191346 A307846
KEYWORD
nonn
AUTHOR
Hans Havermann, Aug 27 2014
STATUS
approved

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Last modified March 2 16:48 EST 2024. Contains 370497 sequences. (Running on oeis4.)