This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A023989 Look and Say sequence: describe the previous term! (method C - initial term is 2). 6
 2, 12, 1112, 3112, 211213, 312213, 212223, 114213, 31121314, 41122314, 31221324, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314, 21322314 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS Method C = 'frequency' followed by 'digit'-indication with digits in increasing order. Converges to 21322314 at the eleventh term. Depending on the initial value, the sequence may converge to a cycle of 2 or more values, for example : 123456, 111213141516, 711213141516, 611213141516, 611213141526, 512213141526, 413213142516, 412223241516, 314213241516, 412223241516, 314213241516, 412223241516 a(n) = A005151(n) for n > 6. - Reinhard Zumkeller, Jan 26 2014 LINKS EXAMPLE a(1) = 12, so a(2) = 1112 because 12 contains a digit 1 and a digit 2; a(3) = 3112 because 1112 contains three digits 1 and a digit 2 MAPLE P:=proc(q, h) local a, b, c, k, n, x; x:=[h]; for n from 1 to q do a:=convert(x[n], base, 10); b:=0; for k from 0 to 9 do c:=numboccur(a, k); if c>0 then b:=b*10^(ilog10(c*10+k)+1)+c*10+k; fi; od; x:=[op(x), b];   od; print(op(x)); end: P(27, 2); # Paolo P. Lava, Aug 30 2018 PROG (Haskell) import Data.List (group, sort, transpose) a023989 n = a023989_list !! (n-1) a023989_list = 2 : f [2] :: [Integer] where    f xs = (read \$ concatMap show ys) : f (ys) where           ys = concat \$ transpose [map length zss, map head zss]           zss = group \$ sort xs -- Reinhard Zumkeller, Jan 26 2014 CROSSREFS Cf. A005150, A022481. Cf. A045918, A118628. Sequence in context: A057120 A112512 A006751 * A001389 A022914 A177361 Adjacent sequences:  A023986 A023987 A023988 * A023990 A023991 A023992 KEYWORD nonn,base AUTHOR Artemario Tadeu Medeiros da Silva (artemario(AT)uol.com.br), Mar 19 2002 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 25 03:10 EDT 2019. Contains 326318 sequences. (Running on oeis4.)