Look-and-say sequence: Difference between revisions

Implementation treating the sequence as numbers

<syntaxhighlight lang="maxima">

ciphers(n):=block(makelist(floor(mod(n, 10^(k+1)) / 10^k), k, 0,floor(log(n)/log(10))),reverse(%%));

collect(a) := block(

[n: length(ciphers(a)), b: [ ], x: ciphers(a)[1], m: 1],

for i from 2 thru n do

(if ciphers(a)[i] = x then m: m + 1 else (b: endcons([x, m], b), x: ciphers(a)[i], m: 1)),

b: endcons([x, m], b),

map(reverse,%%),

flatten(%%),

at(sum((part(%%,k))*y^(length(%%)-k),k,1,length(%%)),y=10)

)$

block(i:1,makelist(i:collect(i),10),table_form(%%));

/* matrix(

[11],

[21],

[1211],

[111221],

[312211],

[13112221],

[1113213211],

[31131211131221],

[13211311123113112211],

[11131221133112132113212221]

) */

</syntaxhighlight>