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 A029805 #35 Feb 12 2025 11:21:29
%S A029805 0,1,2,3,6,9,11,27,65,73,79,81,83,195,219,237,366,513,543,585,697,
%T A029805 1094,1539,1755,1875,2910,4097,4161,4225,4477,4617,4681,4727,4891,
%U A029805 5267,8698,8730,11841,12291,12483,12675,13065,13851,14673,15021
%N A029805 Numbers k such that k^2 is palindromic in base 8.
%C A029805 The only powers of 2 in this sequence are 1 and 2. - _Alonso del Arte_, Feb 25 2017
%H A029805 Seiichi Manyama, <a href="/A029805/b029805.txt">Table of n, a(n) for n = 1..100</a>
%H A029805 Patrick De Geest, <a href="https://www.worldofnumbers.com/nobase10pg2.htm">Palindromic Squares in bases 2 to 17</a>
%e A029805 3 is in the sequence because 3^2 = 9 = 11 in base 8, which is a palindrome.
%e A029805 4 is not in the sequence because 4^2 = 16 = 20 in base 8, which is not a palindrome.
%t A029805 palQ[n_, b_:10] := Module[{idn = IntegerDigits[n, b]}, idn == Reverse[idn]]; Select[Range[0, 16000], palQ[#^2, 8] &] (* _Harvey P. Dale_, May 19 2012 *)
%o A029805 (Python)
%o A029805 from itertools import count, islice
%o A029805 def A029805_gen(): # generator of terms
%o A029805 return filter(lambda k: (s:=oct(k**2)[2:])[:(t:=(len(s)+1)//2)]==s[:-t-1:-1],count(0))
%o A029805 A029805_list = list(islice(A029805_gen(),20)) # _Chai Wah Wu_, Jun 23 2022
%Y A029805 Cf. A000290, A002441, A007094.
%Y A029805 Numbers k such that k^2 is palindromic in base b: A003166 (b=2), A029984 (b=3), A029986 (b=4), A029988 (b=5), A029990 (b=6), A029992 (b=7), this sequence (b=8), A029994 (b=9), A002778 (b=10), A029996 (b=11), A029737 (b=12), A029998 (b=13), A030072 (b=14), A030073 (b=15), A029733 (b=16), A118651 (b=17).
%K A029805 nonn,base
%O A029805 1,3
%A A029805 _Patrick De Geest_