cp's OEIS Frontend

A262712 Numbers k such that sum of digits of k^2 is 9.

%I A262712 #23 Aug 19 2025 10:40:48
%S A262712 3,6,9,12,15,18,21,30,39,45,48,51,60,90,102,105,111,120,150,180,201,
%T A262712 210,249,300,318,321,348,351,390,450,480,501,510,549,600,900,1002,
%U A262712 1005,1011,1020,1050,1101,1110,1149,1200,1500,1761,1800,2001,2010,2100,2490
%N A262712 Numbers k such that sum of digits of k^2 is 9.
%C A262712 Subsequence of A008585.
%H A262712 Robert Israel, <a href="/A262712/b262712.txt">Table of n, a(n) for n = 1..1000</a>
%e A262712 6 is in sequence because 6^2 = 36 and 3+6 = 9.
%p A262712 filter:= proc(n) convert(convert(n^2,base,10),`+`) = 9 end proc:select(filter, [$1..10^5]); # _Robert Israel_, Jan 04 2024
%t A262712 Select[Range[10^5], Total[IntegerDigits[#^2]] == 9 &]
%o A262712 (Magma) [n: n in [1..2*10^4] | &+Intseq(n^2) eq 9 ];
%o A262712 (PARI) for(n=1, 1e8, if (sumdigits(n^2) == 9, print1(n", "))) \\ _Altug Alkan_, Sep 28 2015
%Y A262712 Cf. similar sequences listed in A262711.
%Y A262712 Cf. A004159, A008585, A061910.
%K A262712 nonn,base
%O A262712 1,1
%A A262712 _Vincenzo Librandi_, Sep 28 2015