login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A022470 Describe the previous term! (method B - initial term is 2). 15
2, 21, 2111, 2113, 211231, 2112213111, 211222113113, 21122312311231, 2112223111213112213111, 21122331132111311222113113, 211222321231211331122312311231 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

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

LINKS

Peter J. C. Moses, Table of n, a(n) for n = 1..23

EXAMPLE

E.g. the term after 2113 is obtained by saying "2 once, 1 twice, 3 once", which gives 211231.

MATHEMATICA

a[1] = 2; a[n_] := a[n] = FromDigits[Flatten[{First[#], Length[#]} & /@ Split[IntegerDigits[a[n - 1]]]]]; Map[a, Range[1, 23]] (* Peter J. C. Moses, Mar 22 2013 *)

CROSSREFS

Cf. A007651, A022499, A022500-A022505.

Cf. A006751 (method A).

Sequence in context: A264066 A052157 A050204 * A080815 A276654 A114846

Adjacent sequences:  A022467 A022468 A022469 * A022471 A022472 A022473

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 May 21 14:54 EDT 2019. Contains 323443 sequences. (Running on oeis4.)