A122465 Smooth Power Quartets: The m-th number in the sequence, n, is part of the minimum quartet of numbers n through n-3 such that the highest prime factor of each number x <= floor(x^(1/m)).

5, 1683, 3678726, 22377473783

Offset

1,1

Comments

These were found by R. Gerbicz.

Links

Table of n, a(n) for n=1..4.

Fred Schneider and R. Gerbicz, Smooth Power Trios.

Example

1680 = 2^4*3*5*7, 1681 = 41^2, 1682 = 2*29^2, 1683 = 3^2*11*17; 7 < floor(sqrt(1680)) = 40 and 41 <= floor(sqrt(1681)) = 41, so 1683 is a term.

Crossrefs

Cf. A122463, A122464.

Sequence in context: A237914 A057199 A198246 * A203683 A330057 A324265

Adjacent sequences: A122462 A122463 A122464 * A122466 A122467 A122468

Keyword

hard,more,nonn,uned

Author

Fred Schneider, Sep 09 2006

Status

approved