The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A033010

(Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A033010

Numbers each of whose runs of digits in base 12 has length 2.
(history; published version)

#20 by Peter Luschny at Wed Apr 28 02:43:28 EDT 2021

STATUS

reviewed

approved

#19 by Joerg Arndt at Wed Apr 28 01:31:47 EDT 2021

STATUS

proposed

reviewed

Discussion

Wed Apr 28

02:08

Michel Marcus: Numbers whose all runs of digits in base 12 has length 2  ????

#18 by Michael S. Branicky at Tue Apr 27 20:34:57 EDT 2021

STATUS

editing

proposed

Discussion

Tue Apr 27

22:11

Jon E. Schoenfield: Thanks, Michael -- that sounds like a good option to me.

22:11

Jon E. Schoenfield: 'Any other thoughts on this?

#17 by Michael S. Branicky at Tue Apr 27 20:34:25 EDT 2021

DATA

13, 26, 39, 52, 65, 78, 91, 104, 117, 130, 143, 1872, 1898, 1911, 1924, 1937, 1950, 1963, 1976, 1989, 2002, 2015, 3744, 3757, 3783, 3796, 3809, 3822, 3835, 3848, 3861, 3874, 3887, 5616, 5629, 5642, 5668, 5681, 5694, 5707, 5720, 5733, 5746, 5759, 7488, 7501

PROG

(Python)

from sympy.ntheory import digits

from itertools import groupby

def ok(n):

return all(len(list(g))==2 for k, g in groupby(digits(n, 12)[1:]))

print(list(filter(ok, range(1, 7502)))) # Michael S. Branicky, Apr 27 2021

STATUS

proposed

editing

#16 by Jon E. Schoenfield at Tue Apr 27 20:12:11 EDT 2021

STATUS

editing

proposed

Discussion

Tue Apr 27

20:14

Jon E. Schoenfield: Is this an improvement?  Would something shorter, like "Every run of digits in base 12 has length 2" (where it's just implied that the sequence consists of numbers having that property), be better?

20:21

Michael S. Branicky: Jon, you could follow "A043291: Every run length in base 2 is 2."

#15 by Jon E. Schoenfield at Tue Apr 27 20:11:48 EDT 2021

NAME

Every run Numbers each of whose runs of digits of n in base 12 has length 2.

FORMULA

a(n) = 13*A043316(n) (= 13*n for n < 12). - M. F. Hasler, Feb 02 2014

STATUS

approved

editing

Discussion

Tue Apr 27

20:12

Jon E. Schoenfield: The existing Name uses "n" but doesn't need it...

#14 by Joerg Arndt at Wed Feb 05 03:49:00 EST 2014

STATUS

proposed

approved

#13 by Vincenzo Librandi at Wed Feb 05 03:08:37 EST 2014

STATUS

editing

proposed

#12 by Vincenzo Librandi at Wed Feb 05 03:08:21 EST 2014

LINKS

Vincenzo Librandi, <a href="/A033010/b033010.txt">Table of n, a(n) for n = 1..1400</a>

MATHEMATICA

Select[Range[10000], Union[Length/@Split[IntegerDigits[#, 12]]]=={2}&] (* Vincenzo Librandi, Feb 05 2014 *)

STATUS

approved

editing

#11 by M. F. Hasler at Tue Feb 04 07:08:52 EST 2014

STATUS

editing

approved