This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A023753 #28 Apr 08 2025 17:15:45
%S A023753 0,1,2,3,4,5,6,7,8,9,10,11,13,14,15,16,17,18,19,20,21,22,23,26,27,28,
%T A023753 29,30,31,32,33,34,35,39,40,41,42,43,44,45,46,47,52,53,54,55,56,57,58,
%U A023753 59,65,66,67,68,69,70,71,78,79,80,81,82,83,91,92,93,94,95,104
%N A023753 Plaindromes: numbers whose digits in base 12 are in nondecreasing order.
%H A023753 Vincenzo Librandi, <a href="/A023753/b023753.txt">Table of n, a(n) for n = 1..10000</a>
%t A023753 Select[Range[0,104],LessEqual@@IntegerDigits[#,12]&] (* _Ray Chandler_, Jan 06 2014 *)
%t A023753 Select[Range[0,120],Min[Differences[IntegerDigits[#,12]]]>-1&] (* _Harvey P. Dale_, Jul 10 2023 *)
%o A023753 (PARI) is(n)=vecsort(n=digits(n,12))==n
%o A023753 for(n=0,2,forvec(d=vector(n,i,[1,11]),print1(fromdigits(d,12)","),1)) \\ _M. F. Hasler_, May 05 2020
%o A023753 (Python)
%o A023753 from itertools import count, islice, combinations_with_replacement
%o A023753 def A023753_gen(): # generator of terms
%o A023753 yield 0
%o A023753 yield from (int(''.join(c),12) for l in count(1) for c in combinations_with_replacement('123456789ab',l))
%o A023753 A023753_list = list(islice(A023753_gen(),30)) # _Chai Wah Wu_, Apr 08 2025
%Y A023753 Cf. A000225, A023745, ..., A023757 (nondecreasing digits in base 2, 3, ..., 16).
%Y A023753 Cf. A023758, A023759, ..., A023771 (nonincreasing digits in base 2, 3, ..., 16).
%K A023753 nonn,base,easy
%O A023753 1,3
%A A023753 _Olivier Gérard_
%E A023753 Change offset to 1 by _Ray Chandler_, Jan 06 2014