A262712 Numbers k such that sum of digits of k^2 is 9.
3, 6, 9, 12, 15, 18, 21, 30, 39, 45, 48, 51, 60, 90, 102, 105, 111, 120, 150, 180, 201, 210, 249, 300, 318, 321, 348, 351, 390, 450, 480, 501, 510, 549, 600, 900, 1002, 1005, 1011, 1020, 1050, 1101, 1110, 1149, 1200, 1500, 1761, 1800, 2001, 2010, 2100, 2490
Offset: 1
Examples
6 is in sequence because 6^2 = 36 and 3+6 = 9.
Links
- Robert Israel, Table of n, a(n) for n = 1..1000
Programs
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Magma
[n: n in [1..2*10^4] | &+Intseq(n^2) eq 9 ];
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Maple
filter:= proc(n) convert(convert(n^2,base,10),`+`) = 9 end proc:select(filter, [$1..10^5]); # Robert Israel, Jan 04 2024
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Mathematica
Select[Range[10^5], Total[IntegerDigits[#^2]] == 9 &]
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PARI
for(n=1, 1e8, if (sumdigits(n^2) == 9, print1(n", "))) \\ Altug Alkan, Sep 28 2015
Comments