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Numbers k such that k^2 is palindromic in base 9.
12

%I #18 Oct 16 2021 13:19:54

%S 0,1,2,10,20,82,91,100,164,730,820,1460,6562,6643,6724,7300,7381,7462,

%T 13124,13642,13660,14281,54050,59050,59860,65620,66430,118100,123010,

%U 126286,161410,161896,487750,531442,532171

%N Numbers k such that k^2 is palindromic in base 9.

%H Seiichi Manyama, <a href="/A029994/b029994.txt">Table of n, a(n) for n = 1..100</a>

%H Patrick De Geest, <a href="http://www.worldofnumbers.com/square.htm">Palindromic Squares</a>

%t pb9Q[n_]:=Module[{idn=IntegerDigits[n^2,9]},idn==Reverse[idn]]; Select[ Range[0,600000],pb9Q] (* _Harvey P. Dale_, Sep 29 2013 *)

%Y Cf. A007095.

%Y 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), A029805 (b=8), this sequence (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 nonn,base

%O 1,3

%A _Patrick De Geest_