cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

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

Original entry on oeis.org

4058471, 91, 3854, 178086, 15469622, 18230787183
Offset: 1

Views

Author

Hans Havermann, Aug 27 2014

Keywords

Comments

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

Examples

			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.

A246548 Start of the least 5-tuple of consecutive squarefree numbers each of which has exactly n distinct prime factors.

Original entry on oeis.org

462807341, 115, 6302, 294590, 106985762
Offset: 1

Views

Author

Hans Havermann, Aug 29 2014

Keywords

Comments

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

Examples

			462807341, 462807343, 462807347, 462807349, and 462807353 are the smallest 5 primes that are also consecutive squarefree numbers, so a(1) = 462807341.
115, 118, 119, 122, and 123 are the smallest 5 semiprimes that are also consecutive squarefree numbers, so a(2) = 115.
6302, 6303, 6305, 6306, and 6307 is the smallest 5-tuple of consecutive squarefree numbers each of which has exactly 3 prime factors, so a(3) = 6302.

Crossrefs

Cf. A005117, A242621 (triple version), A246470 (quadruplet version), A246471.
Showing 1-2 of 2 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.