A240595 Look-and-Say table, where in row(n+1) the sorted list of distinct terms of row(n) is preceded by the list of numbers of their occurrences.

1, 1, 1, 2, 1, 1, 1, 1, 2, 3, 1, 1, 2, 2, 1, 1, 1, 2, 3, 3, 2, 1, 1, 2, 3, 2, 2, 2, 1, 2, 3, 1, 4, 1, 1, 2, 3, 3, 1, 1, 1, 1, 2, 3, 4, 4, 1, 2, 1, 1, 2, 3, 4, 3, 2, 1, 2, 1, 2, 3, 4, 2, 3, 2, 1, 1, 2, 3, 4, 2, 3, 2, 1, 1, 2, 3, 4, 2, 3, 2, 1, 1, 2, 3, 4, 2

Offset

1,4

Comments

For n > 13: row(n) = row(13), see example.

Links

Table of n, a(n) for n=1..86.

Eric Weisstein's World of Mathematics, Look and Say Sequence

Wikipedia, Look-and-say sequence

Example

.  1: [1] -> 1x1 -> [1 | 1] -> row(2)
.  2: [1,1] -> 2x1 -> [2 | 1] -> row(3)
.  3: [2,1] -> 1x1, 1x2 -> [1,1 | 1,2] -> row(4)
.  4: [1,1,1,2] -> 3x1, 1x2 -> [3,1 | 1,2] -> row(5)
.  5: [3,1,1,2] -> 2x1, 1x2, 1x3 -> [2,1,1 | 1,2,3] -> row(6)
.  6: [2,1,1,1,2,3] -> 3x1, 2x2, 1x3 -> [3,2,1 | 1,2,3] -> row(7)
.  7: [3,2,1,1,2,3] -> 2x1, 2x2, 2x3 -> [2,2,2 | 1,2,3] -> row(8)
.  8: [2,2,2,1,2,3] -> 1x1, 4x2, 1x3 -> [1,4,1 | 1,2,3] -> row(9)
.  9: [1,4,1,1,2,3] -> 3x1, 1x2, 1x3, 1x4 -> [3,1,1,1 | 1,2,3] -> row(10)
. 10: [3,1,1,1,1,2,3,4] -> 4x1, 1x2, 2x3, 1x4 -> [4,1,2,1 | 1,2,3,4]
. 11: [4,1,2,1,1,2,3,4] -> 3x1, 2x2, 1x3, 2x4 -> [3,2,1,2 | 1,2,3,4]
. 12: [3,2,1,2,1,2,3,4] -> 2x1, 3x2, 2x3, 1x4 -> [2,3,2,1 | 1,2,3,4]
. 13: [2,3,2,1,1,2,3,4] -> 2x1, 3x2, 2x3, 1x4 -> [2,3,2,1 | 1,2,3,4]
. 14: [2,3,2,1,1,2,3,4] = row(13).

Prog

(Haskell)
import Data.List (sort, group)
a240595 n k = a240595_tabf !! (n-1) !! (k-1)
a240595_row n = a240595_tabf !! (n-1)
a240595_tabf = iterate f [1] where
   f xs = concat [map length zss, map head zss]
          where zss = group $ sort xs

Crossrefs

Cf. A034002.

Sequence in context: A303929 A303694 A194673 * A083671 A201913 A232463

Adjacent sequences: A240592 A240593 A240594 * A240596 A240597 A240598

Keyword

nonn,tabf

Author

Reinhard Zumkeller, Apr 08 2014

Status

approved