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highly composite number (Definition)

We call $n$ a highly composite number if $d(n)>d(m)$ for all $m<n$, where $d(n)$ is the number of divisors of $n$. The first several are 1, 2, 4, 6, 12, 24. The sequence is A002182 in Sloane's OEIS.

The integer $n$ is superior highly composite if there is an $\epsilon>0$ such that for all $m\not=n$,

\begin{displaymath}d(n) n^{-\epsilon} > d(m) m^{-\epsilon}.\end{displaymath}

The first several superior highly composite numbers are 2, 6, 12, 60, 120, 360. The sequence is A002201 in Sloane's encyclopedia.

Bibliography

1
L. Alaoglu and P. Erdös, On highly composite and similar numbers. Trans. Amer. Math. Soc. 56 (1944), 448-469. Available at www.jstor.org



"highly composite number" is owned by Kevin OBryant.
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Also defines:  superior highly composite number
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Cross-references: composite, integer, OEIS, sequence, divisors, number
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This is version 4 of highly composite number, born on 2003-06-11, modified 2006-12-08.
Object id is 4347, canonical name is HighlyCompositeNumber.
Accessed 7212 times total.

Classification:
AMS MSC11N56 (Number theory :: Multiplicative number theory :: Rate of growth of arithmetic functions)

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