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A057144 Smallest of the most frequently occurring numbers in 1-to-n multiplication table. 9
1, 2, 2, 4, 4, 6, 6, 6, 6, 6, 6, 12, 12, 12, 12, 12, 12, 36, 36, 60, 60, 60, 60, 24, 24, 24, 24, 24, 24, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120, 120 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

EXAMPLE

M(n) is the array in which m(x,y)= x*y for x = 1 to n and y = 1 to n. In m(10), the most frequently occurring numbers are 6, 8, 10, 12, 18, 20, 24, 30,40, each occurring 4 times. The smallest of these numbers is 6, so a(10) = 6.

PROG

(Haskell)

import Data.List (sort, group, sortBy, groupBy)

import Data.Function (on)

a057144 n = head $ last $ head $ groupBy ((==) `on` length) $

            reverse $ sortBy (compare `on` length) $

            group $ sort [u * v | u <- [1..n], v <- [1..n]]

-- Reinhard Zumkeller, Jun 22 2013

CROSSREFS

Cf. A057142, A057143, A057338.

Sequence in context: A069345 A007730 A257686 * A198332 A080606 A083535

Adjacent sequences:  A057141 A057142 A057143 * A057145 A057146 A057147

KEYWORD

nonn

AUTHOR

Arran Fernandez, Aug 13 2000

EXTENSIONS

More terms from Larry Reeves (larryr(AT)acm.org), Apr 18 2001

STATUS

approved

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Last modified May 21 15:06 EDT 2019. Contains 323443 sequences. (Running on oeis4.)