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A193429
a(n) = minimum value of the largest element of a nonempty set of positive integers > n such that their product is equal to n!, or 0 if no such set exists.
1
1, 0, 0, 6, 24, 12, 10, 20, 16, 28, 25, 22, 33, 30, 28, 28, 39, 35, 36, 44, 44, 42, 44, 50, 50, 50, 57, 57, 56, 58, 65, 64, 64, 72, 72, 70, 75, 80, 80, 78, 80, 88, 88, 86, 88, 95, 95, 94, 96, 102, 104, 102, 104, 111, 111, 110, 112, 120, 119, 118, 120, 122, 125
OFFSET
0,4
COMMENTS
For n > 4, there is always the factorization n! = (2*n) * (n!/(2*n)), so a(n) is only 0 for n = 1 or 2. - Franklin T. Adams-Watters, Jul 28 2011.
It appears that this sequence is O(n). - Franklin T. Adams-Watters, Jul 28 2011.
LINKS
EXAMPLE
For n=5, n! = 120. Any factorization of 120 into 3 (or more) factors will have a factor <= 5, so we take the most central factorization into two factors, 120 = 10*12, the maximum of {10, 12} is 12, thus a(5) = 12.
CROSSREFS
Sequence in context: A293256 A213344 A337023 * A213278 A029592 A112034
KEYWORD
nonn
AUTHOR
STATUS
approved