A136339 a(1) = 1; for all n >= 2, we choose a(n) to be as small as possible so that for all i = 1, ..., n, the sequence of the i-th divisors of a(1), a(2), ..., a(n) is nonincreasing.

1, 2, 4, 6, 12, 24, 48, 60, 120, 240, 360, 720, 1260, 1680, 2520, 5040, 10080, 15120, 25200, 27720, 55440, 110880, 166320, 277200, 554400, 720720, 1441440, 2162160, 3603600, 7207200, 10810800, 21621600, 43243200, 73513440, 122522400

Offset

1,2

Comments

The original definition of this sequence was: a(n+1) = smallest number such that the d-th divisors of a(n), a(n+1) will never increase. [What is d?]

Similar to A094783, except that only members of the sequence can disqualify larger numbers.

Links

Table of n, a(n) for n=1..35.

Example

What is a(13), the term after 720? It cannot be 840 because 720's 13th smallest divisor is 18 and 840's 13th smallest divisor is 20 > 18.

Crossrefs

Cf. A094783.

Sequence in context: A375438 A095848 A208767 * A019505 A350049 A135614

Adjacent sequences: A136336 A136337 A136338 * A136340 A136341 A136342

Keyword

nonn

Author

J. Lowell, Mar 28 2008

Extensions

Edited by N. J. A. Sloane, Apr 04 2008. I tried to rewrite the definition to make it precise, but I am not sure I have done this correctly.

More terms from Hagen von Eitzen, Oct 03 2009

Status

approved