login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A321803 Keep only consecutive identical decimal digits of n; write 0 if all digits disappear. 2
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 33, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 55, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 66, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 77, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 99, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 11, 111, 11, 11, 11, 11, 11, 11, 11, 11, 0, 0, 22, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 33, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 44, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 55, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 66, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 77, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 99 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,12
COMMENTS
Consecutive identical digits of n are kept. Leading zeros are erased unless the result is 0. If all digits are erased, we write 0 for the result (A321804 is another version, which uses -1 for the empty string).
More than the usual number of terms are shown in order to reach some interesting examples. Agrees with A321797 for n < 121.
Differs from A321538 for the first time at n = 11011. - Chai Wah Wu, Nov 29 2018
LINKS
EXAMPLE
123321 becomes 33, 1123 becomes 11, 112331 becomes 1133, and 100223 becomes 22 (as we don't accept leading zeros). Note that 12321 disappears immediately and we get 0.
MATHEMATICA
Array[FromDigits[Join @@ Select[Split@ IntegerDigits@ #, Length@ # >= 2 &] /. {} -> {0}] &, 200, 0] (* Michael De Vlieger, Nov 20 2018 *)
PROG
(Python)
from re import split
def A321803(n):
return int('0'+''.join(d if len(d) != 1 else '' for d in split('(0+)|(1+)|(2+)|(3+)|(4+)|(5+)|(6+)|(7+)|(8+)|(9+)', str(n)) if d != '' and d != None))
CROSSREFS
Sequence in context: A259391 A279540 A321538 * A321797 A113043 A110408
KEYWORD
nonn,base
AUTHOR
Chai Wah Wu, Nov 19 2018
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 18 22:48 EDT 2024. Contains 370951 sequences. (Running on oeis4.)