A057143 Largest of the most frequently occurring numbers in 1-to-n multiplication table.

1, 2, 6, 4, 4, 12, 12, 24, 24, 40, 40, 24, 24, 24, 60, 60, 60, 36, 36, 60, 60, 60, 60, 120, 120, 120, 120, 168, 168, 120, 120, 120, 120, 120, 120, 180, 180, 180, 180, 120, 120, 120, 120, 120, 360, 360, 360, 360, 360, 360, 360, 360, 360, 360, 360, 360, 360, 360

Offset

1,2

Links

Branden Aldridge, Table of n, a(n) for n = 1..20000 (first 1000 terms from Reinhard Zumkeller).

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 largest of these numbers is 40, so a(10) = 40.

Prog

(Haskell)
import Data.List (group, sort, sortBy)
import Data.Function (on)
a057143 n = head $ head $ reverse $ sortBy (compare `on` length) $
            group $ sort [u * v | u <- [1..n], v <- [1..n]]
-- Reinhard Zumkeller, Jun 22 2013

Crossrefs

Cf. A057142, A057144, A057338.

Sequence in context: A249913 A003077 A323482 * A087428 A115508 A348669

Adjacent sequences: A057140 A057141 A057142 * A057144 A057145 A057146

Keyword

nonn

Author

Arran Fernandez, Aug 13 2000

Extensions

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

Status

approved