Look-and-say sequence
E29421
The look-and-say sequence is a famous integer sequence where each term is generated by verbally describing the digits of the previous term, studied for its surprising combinatorial and growth properties.
All labels observed (5)
| Label | Occurrences |
|---|---|
| Conway constant | 2 |
| A005150 | 1 |
| Conway sequence | 1 |
| Look-and-say sequence canonical | 1 |
| look and say sequence | 1 |
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
combinatorial object
ⓘ
integer sequence ⓘ recursively defined sequence ⓘ |
| alsoKnownAs |
Look-and-say sequence
ⓘ
surface form:
Conway sequence
Look-and-say sequence ⓘ
surface form:
look and say sequence
|
| definedByRule | each term describes the digits of the previous term in order of appearance ⓘ |
| growthConstantName |
Look-and-say sequence
self-linksurface differs
ⓘ
surface form:
Conway constant
|
| hasApproximateConwayConstant | 1.303577269034 ⓘ |
| hasAsymptoticBehavior | length of nth term grows like lambda^n where lambda is the Conway constant ⓘ |
| hasCombinatorialStructure | decomposes into irreducible subsequences called atoms ⓘ |
| hasConstructionMethod | start with a seed term and iteratively describe runs of identical digits ⓘ |
| hasDescriptionLanguage | English digit names and counts ⓘ |
| hasDigitAlphabet |
1
ⓘ
2 ⓘ 3 ⓘ |
| hasExampleTerm |
1113213211
ⓘ
13112221 ⓘ 312211 ⓘ |
| hasFifthTerm | 111221 ⓘ |
| hasFirstTerm | 1 ⓘ |
| hasFourthTerm | 1211 ⓘ |
| hasGeneralization |
look-and-say sequences in other bases
ⓘ
look-and-say sequences using other symbol alphabets ⓘ |
| hasGrowthRate | approximately 1.303577269 ⓘ |
| hasMathematicalArea |
combinatorics
ⓘ
discrete mathematics ⓘ number theory ⓘ |
| hasNamedConstant |
Look-and-say sequence
self-linksurface differs
ⓘ
surface form:
Conway constant
|
| hasOEISId |
Look-and-say sequence
self-linksurface differs
ⓘ
surface form:
A005150
|
| hasProperty |
admits a finite set of irreducible elements under the evolution rule
ⓘ
different seeds lead to different look-and-say sequences ⓘ digits eventually stabilize to a finite set of allowed blocks ⓘ local patterns evolve independently in the limit ⓘ no term contains the digit 4 or higher when written in standard form ⓘ sequence is not eventually periodic ⓘ terms do not converge in value but lengths diverge to infinity ⓘ terms grow in length roughly exponentially ⓘ |
| hasSecondTerm | 11 ⓘ |
| hasThirdTerm | 21 ⓘ |
| isDescribedIn | On Numbers and Games ⓘ |
| isFamousFor |
nontrivial asymptotic growth analysis by Conway
ⓘ
unexpected regularities in digit patterns ⓘ |
| isRelatedTo |
cellular automata
ⓘ
formal languages ⓘ run-length encoding ⓘ |
| studiedBy |
John H. Conway
ⓘ
surface form:
John Horton Conway
|
| typicalSeed | 1 ⓘ |
Referenced by (6)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
look and say sequence
this entity surface form:
Conway sequence
this entity surface form:
A005150
this entity surface form:
Conway constant
this entity surface form:
Conway constant