A138489
Say what you see in previous term, from the right, reporting total number for each digit encountered. Initial term is 5.
Original entry on oeis.org
5, 15, 1511, 3115, 152113, 13311215, 15411223, 1322311415, 1541142322, 3213243115, 1531331422, 2214313315, 1531331422, 2214313315, 1531331422, 2214313315, 1531331422, 2214313315, 1531331422, 2214313315, 1531331422
Offset: 0
To get the term after 152113, we say: one 3's, three 1's, one 2's, one 5's, so 13311215
A138490
Say what you see in previous term, from the right, reporting total number for each digit encountered. Initial term is 6.
Original entry on oeis.org
6, 16, 1611, 3116, 162113, 13311216, 16411223, 1322311416, 1641142322, 3213243116, 1631331422, 2214313316, 1631331422, 2214313316, 1631331422, 2214313316, 1631331422, 2214313316, 1631331422, 2214313316, 1631331422
Offset: 0
To get the term after 162113, we say: one 3's, three 1's, one 2's, one 6's, so 13311216
A138491
Say what you see in previous term, from the right, reporting total number for each digit encountered. Initial term is 7.
Original entry on oeis.org
7, 17, 1711, 3117, 172113, 13311217, 17411223, 1322311417, 1741142322, 3213243117, 1731331422, 2214313317, 1731331422, 2214313317, 1731331422, 2214313317, 1731331422, 2214313317, 1731331422, 2214313317, 1731331422
Offset: 0
To get the term after 172113, we say: one 3's, three 1's, one 2's, one 7's, so 13311217
Cf.
A063850,
A022482,
A005150,
A005151,
A006751,
A006715,
A006711,
A022506-
A022513,
A138484-
A138490,
A138492,
A138493.
A138492
Say what you see in previous term, from the right, reporting total number for each digit encountered. Initial term is 8.
Original entry on oeis.org
8, 18, 1811, 3118, 182113, 13311218, 18411223, 1322311418, 1841142322, 3213243118, 1831331422, 2214313318, 1831331422, 2214313318, 1831331422, 2214313318, 1831331422, 2214313318, 1831331422, 2214313318, 1831331422
Offset: 0
To get the term after 182113, we say: one 3's, three 1's, one 2's, one 8's, so 13311218
A363054
Look and say sequence: describe the previous term (method A, starting with 20).
Original entry on oeis.org
20, 1210, 11121110, 31123110, 132112132110, 11131221121113122110, 311311222112311311222110, 1321132132211213211321322110, 11131221131211132221121113122113121113222110, 3113112221131112311332211231131122211311123113322110
Offset: 1
The term after 1210 is given by saying "I see one 1, one 2, one 1, and one 0", and then writing down the digits as 11-12-11-10, yielding 11121110.
- Michael De Vlieger, Table of n, a(n) for n = 1..21
- Julia Witte Zimmerman, Denis Hudon, Kathryn Cramer, Alejandro J. Ruiz, Calla Beauregard, Ashley Fehr, Mikaela Irene Fudolig, Bradford Demarest, Yoshi Meke Bird, Milo Z. Trujillo, Christopher M. Danforth, and Peter Sheridan Dodds, Tokens, the oft-overlooked appetizer: Large language models, the distributional hypothesis, and meaning, arXiv:2412.10924 [cs.CL], 2024. See pp. 21, 28.
Other look-and-say sequences:
A005150,
A001155,
A006751,
A006715,
A001140,
A001141,
A001143,
A001145,
A001151,
A007651,
A001387,
A098595,
A045918.
-
NestList[FromDigits@ Flatten@ Map[Reverse@ Tally[#][[1]] &, Split@ IntegerDigits[#] ] &, 20, 12] (* Michael De Vlieger, Jul 05 2023 *)
-
from itertools import count, groupby, islice
def LS(n): return int(''.join(str(len(list(g)))+k for k, g in groupby(str(n))))
def agen(an=20): yield an; yield from (an:=LS(an) for n in count(1))
print(list(islice(agen(), 10))) # Michael S. Branicky, May 15 2023
Original entry on oeis.org
10, 1100, 2000, 129000, 1112990000, 310198100000, 12900010100000, 1113122099909791900000, 31130009089198002000100000, 132082082098921801009009900000, 11131221131211000108018890978199979090100000, 31131122211299991892189900998999891000999919009909900000
Offset: 1
a(1) = A006751(2) - A006751(1) = 12 - 2 = 10.
a(2) = A006751(3) - A006751(2) = 1112 - 12 = 1100.
-
f[n_, d_: 1] := NestList[Flatten[Reverse /@ Map[Function[k, Through[{First, Length}@ k]], Split@ #]] &, {d}, n - 1]; Differences@ Array[FromDigits@ f[#, 2][[#]] &, {13}] (* Michael De Vlieger, Jan 03 2016, after Zerinvary Lajos at A006751 *)
-
dpt(n) = {vd = []; d = digits(n); nbd = 0; old = -1; for (k=1, #d, if (d[k] == old, nbd ++, if (old != -1, vd = concat(vd, nbd); vd = concat(vd, old);); nbd = 1;); old = d[k];); vd = concat(vd, nbd); vd = concat(vd, old); subst(Pol(vd), x, 10);}
lista(nn, x=2) = {v = vector(nn); v[1] = x; for (n=2, nn, nx = dpt(x); v[n] = nx; x = nx;); vector(nn-1, n, v[n+1] - v[n]);} \\ 2nd param x can any value between 2 and 9 \\ Michel Marcus, Dec 16 2015
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