A193459 Total number of distinct divisors of all numbers that can be written by rearranging the digits of n in decimal representation.

1, 2, 2, 3, 2, 4, 2, 4, 3, 4, 2, 8, 3, 5, 6, 6, 3, 8, 5, 6, 8, 4, 7, 12, 8, 6, 13, 8, 7, 8, 3, 7, 4, 5, 5, 12, 3, 5, 6, 8, 5, 12, 5, 6, 11, 9, 5, 16, 6, 6, 6, 8, 5, 11, 4, 11, 8, 7, 5, 12, 6, 6, 12, 9, 11, 8, 7, 8, 14, 8, 3, 13, 3, 5, 8, 7, 4, 10, 3, 10, 8

Offset

1,2

Comments

a(n) >= A000005(n), a(A193460(n)) = A000005(A193460(n)).

Links

Reinhard Zumkeller, Table of n, a(n) for n = 1..10000

Example

a(20) = #{1,2,4,5,10,20} = 6;
a(21) = #{1,2,3,4,6,7,12,21} = 8;
a(22) = #{1,2,11,22} = 4;
a(23) = #{1,2,4,8,16,23,32} = 7;
a(24) = #{1,2,3,4,6,7,8,12,14,21,24,42} = 12;
a(25) = #{1,2,4,5,13,25,26,52} = 8;
a(26) = #{1,2,13,26,31,62} = 6;
a(27) = #{1,2,3,4,6,8,9,12,18,24,27,36,72} = 13;
a(28) = #{1,2,4,7,14,28,41,82} = 8;
a(29) = #{1,2,4,23,29,46,92} = 7.

Prog

(Haskell)
import Data.List (permutations, nub)
a193459 n =
   length $ nub $ concatMap divisors $ map read $ permutations $ show n
      where divisors n = filter ((== 0) . mod n) [1..n]
a193459_list = map a193459 [1..]

Crossrefs

Cf. A047726.

Sequence in context: A066800 A368195 A218705 * A114102 A193513 A218704

Adjacent sequences: A193456 A193457 A193458 * A193460 A193461 A193462

Keyword

nonn,base,look

Author

Reinhard Zumkeller, Jul 26 2011

Status

approved