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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

%I #9 Mar 31 2012 14:12:21

%S 1,2,4,6,12,24,48,60,120,240,360,720,1260,1680,2520,5040,10080,15120,

%T 25200,27720,55440,110880,166320,277200,554400,720720,1441440,2162160,

%U 3603600,7207200,10810800,21621600,43243200,73513440,122522400

%N 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.

%C 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?]

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

%e 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.

%Y Cf. A094783.

%K nonn

%O 1,2

%A _J. Lowell_, Mar 28 2008

%E 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.

%E More terms from _Hagen von Eitzen_, Oct 03 2009

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Last modified April 24 16:56 EDT 2024. Contains 371962 sequences. (Running on oeis4.)