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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. 0
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 (list; graph; refs; listen; history; text; internal format)
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: A068010 A095848 A208767 * A019505 A135614 A115387

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

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Last modified March 30 19:43 EDT 2020. Contains 333127 sequences. (Running on oeis4.)