A246470 Start of the least quadruplet of consecutive squarefree numbers each of which has exactly n distinct prime factors.

4058471, 91, 3854, 178086, 15469622, 18230787183

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 (5-tuple 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