login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo

Please make a donation to keep the OEIS running. We are now in our 56th year. In the past year we added 10000 new sequences and reached almost 9000 citations (which often say "discovered thanks to the OEIS").
Other ways to donate

Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A022482 Describe previous term from the right (method A - initial term is 2). 25
2, 12, 1211, 211211, 21122112, 1221222112, 122132112211, 2122211213112211, 21222113111221321112, 123112131122311321321112, 123112131112132113222113111221131211 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Method A = 'frequency' followed by 'digit'-indication.

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..22

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

Wikipedia, Look-and-say sequence

FORMULA

a(n+1) = A045918(A004086(a(n))). - Reinhard Zumkeller, Mar 02 2014

EXAMPLE

E.g. the term after 1211 is obtained by saying "two 1's, one 2, one 1", which gives 211211.

MATHEMATICA

A022482[1]:=2; A022482[n_]:=A022482[n]=FromDigits[Flatten[{Length[#], First[#]}&/@Split[Reverse[IntegerDigits[A022482[n-1]]]]]]; Map[A022482, Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)

PROG

(Haskell)

a022482 n = a022482_list !! (n-1)

a022482_list = iterate (a045918 . a004086) 2

-- Reinhard Zumkeller, Mar 02 2014

CROSSREFS

Cf. A022506, A006711, A022507-A022513.

Sequence in context: A022914 A177361 A138486 * A081701 A069714 A176391

Adjacent sequences:  A022479 A022480 A022481 * A022483 A022484 A022485

KEYWORD

nonn,base,easy,nice

AUTHOR

Clark Kimberling

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.

License Agreements, Terms of Use, Privacy Policy. .

Last modified November 27 15:11 EST 2020. Contains 338683 sequences. (Running on oeis4.)