login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A022515 Describe previous term from the right (method B - initial term is 4). 5
4, 41, 1141, 114112, 21124112, 211241211221, 112212211141211221, 1122122111411322112212, 21112212223112411322112212, 21112212223112412112312311221321 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
Method B = 'digit'-indication followed by 'frequency'.
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 0..21
EXAMPLE
The term after 1141 is obtained by saying "1 once, 4 once, 1 twice", which gives 114112.
MATHEMATICA
A022515[1]:=4; A022515[n_]:=A022515[n]=FromDigits[Flatten[{First[#], Length[#]}&/@Split[Reverse[IntegerDigits[A022515[n-1]]]]]]; Map[A022515, Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)
PROG
(Haskell)
import Data.List (group, transpose)
a022515 n = a022515_list !! n
a022515_list = 4 : f [4] :: [Integer] where
f xs = (read $ concatMap show ys) : f ys where
ys = concat $ transpose [map head zss, map length zss]
zss = reverse $ group xs
-- Reinhard Zumkeller, Jan 26 2014
CROSSREFS
Sequence in context: A284276 A327026 A244751 * A172496 A059730 A006825
KEYWORD
nonn,base,easy,nice
AUTHOR
EXTENSIONS
More terms from Patrick De Geest, Jun 15 1999
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 22 09:18 EDT 2024. Contains 374485 sequences. (Running on oeis4.)