A022481
Describe previous term from the right (method B - initial term is 1).
Original entry on oeis.org
1, 11, 12, 2111, 1321, 11213111, 1331112112, 211221133211, 12213212221221, 11221123112131112211, 122213311121123121122212, 211123122111312112211332112311
Offset: 1
E.g. the term after 1321 is obtained by saying "1 once, 2 once, 3 once, 1 once", which gives 11213111.
-
import Data.List (group, transpose)
a022481 n = a022481_list !! (n-1)
a022481_list = 1 : f [1] :: [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
-
A022481[1]:=1;A022481[n_]:=A022481[n]=FromDigits[Flatten[{First[#],Length[#]}&/@Split[Reverse[IntegerDigits[A022481[n-1]]]]]];Map[A022481,Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)
a[1]=1;a[n_]:=a[n]=FromDigits[Flatten[Replace[ Replace[ Replace[ Split[ Reverse[IntegerDigits[a[n-1]]]],{x_,y_}->{x,Length[{x,y}]},{1}],{x_,y_,z_}->{x,Length[{x,y,z}]},{1}],{x_}->{x,Length[{x}]},{1}]]];Array[a,15] (* Ivan N. Ianakiev, Jun 22 2017 *)
NestList[FromDigits@ Flatten@ Reverse@ Map[{First@ #, Length@ #} &, Split@ IntegerDigits@ #] &, 1, 11] (* Michael De Vlieger, Jun 26 2017 *)
A022514
Describe previous term from the right (method B - initial term is 3).
Original entry on oeis.org
3, 31, 1131, 113112, 21123112, 211231211221, 112212211131211221, 1122122111311322112212, 21112212223112311322112212, 21112212223112312112312311221321
Offset: 0
The term after 1131 is obtained by saying "1 once, 3 once, 1 twice", which gives 113112.
-
import Data.List (group, transpose)
a022514 n = a022514_list !! n
a022514_list = 3 : f [3] :: [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
-
A022514[1]:=3;A022514[n_]:=A022514[n]=FromDigits[Flatten[{First[#],Length[#]}&/@Split[Reverse[IntegerDigits[A022514[n-1]]]]]];Map[A022514,Range[15]] (* Peter J. C. Moses, Apr 22 2013 *)
A022520
Describe previous term from the right (method B - initial term is 9).
Original entry on oeis.org
9, 91, 1191, 119112, 21129112, 211291211221, 112212211191211221, 1122122111911322112212, 21112212223112911322112212, 21112212223112912112312311221321
Offset: 0
The term after 1191 is obtained by saying "1 once, 9 once, 1 twice", which gives 119112.
-
import Data.List (group, transpose)
a022520 n = a022520_list !! n
a022520_list = 9 : f [9] :: [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
A022515
Describe previous term from the right (method B - initial term is 4).
Original entry on oeis.org
4, 41, 1141, 114112, 21124112, 211241211221, 112212211141211221, 1122122111411322112212, 21112212223112411322112212, 21112212223112412112312311221321
Offset: 0
The term after 1141 is obtained by saying "1 once, 4 once, 1 twice", which gives 114112.
-
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
-
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 *)
A022519
Describe previous term from the right (method B - initial term is 8).
Original entry on oeis.org
8, 81, 1181, 118112, 21128112, 211281211221, 112212211181211221, 1122122111811322112212, 21112212223112811322112212, 21112212223112812112312311221321
Offset: 0
The term after 1181 is obtained by saying "1 once, 8 once, 1 twice", which gives 118112.
-
import Data.List (group, transpose)
a022519 n = a022519_list !! n
a022519_list = 8 : f [8] :: [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
-
from itertools import groupby
A022519_list = [8]
for _ in range(10):
A022519_list.append(int(''.join(str(k)+str(len(list(g))) for k, g in groupby(str(A022519_list[-1])[::-1])))) # Chai Wah Wu, Sep 01 2021
A022516
Describe previous term from the right (method B - initial term is 5).
Original entry on oeis.org
5, 51, 1151, 115112, 21125112, 211251211221, 112212211151211221, 1122122111511322112212, 21112212223112511322112212, 21112212223112512112312311221321
Offset: 0
The term after 1151 is obtained by saying "1 once, 5 once, 1 twice", which gives 115112.
-
import Data.List (group, transpose)
a022516 n = a022516_list !! n
a022516_list = 5 : f [5] :: [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
A022517
Describe previous term from the right (method B - initial term is 6).
Original entry on oeis.org
6, 61, 1161, 116112, 21126112, 211261211221, 112212211161211221, 1122122111611322112212, 21112212223112611322112212, 21112212223112612112312311221321
Offset: 0
The term after 1161 is obtained by saying "1 once, 6 once, 1 twice", which gives 116112.
-
import Data.List (group, transpose)
a022517 n = a022517_list !! n
a022517_list = 6 : f [6] :: [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
A022518
Describe previous term from the right (method B - initial term is 7).
Original entry on oeis.org
7, 71, 1171, 117112, 21127112, 211271211221, 112212211171211221, 1122122111711322112212, 21112212223112711322112212, 21112212223112712112312311221321
Offset: 0
The term after 1171 is obtained by saying "1 once, 7 once, 1 twice", which gives 117112.
-
import Data.List (group, transpose)
a022518 n = a022518_list !! n
a022518_list = 7 : f [7] :: [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
-
split[n_]:=Split[Reverse[IntegerDigits[n]]];
list1[n_]:=List/@Length/@split[n];riffle1[n_]:=Riffle[split[n],list1[n]];
tab[n_]:=Table[i,{i,1,2*Length[list1[n]],2}];
list2[n_]:=Append[riffle1[n][[#]],riffle1[n][[#+1]]]&/@tab[n];
flat[n_]:=Flatten/@list2[n];riffle2[n_]:=Riffle[First/@flat[n],Last/@flat[n]];
a[1]=7;a[n_]:=FromDigits[riffle2[a[n-1]]];Array[a,10] (* or *)
a[1]=7;a[n_]:=FromDigits[Flatten[Replace[Replace[Replace[Split[Reverse[IntegerDigits[
a[n-1]]]],{x_,y_}-> {x,Length[{x,y}]},{1}],{x_,y_,z_}-> {x,Length[{x,y,z}]},{1}],{x_}-> {x,Length[{x}]},{1}]]];Array[a,10] (* Ivan N. Ianakiev, Oct 07 2016 *)
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