

A202170


Numbers n such that n^2 has only digits 0, 4 and 8.


2



0, 2, 20, 22, 200, 202, 220, 298, 2000, 2002, 2020, 2022, 2200, 2202, 2980, 20000, 20002, 20020, 20022, 20200, 20220, 22000, 22002, 22020, 28998, 29800, 200000, 200002, 200020, 200022, 200200, 200202, 200220, 202000, 202002, 202200, 220000, 220002, 220020, 220200, 289980, 298000, 632522, 2000000
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OFFSET

1,2


COMMENTS

n = 2*m where m^2 has only digits 0, 1 and 2.  Robert Israel, Jul 17 2018


LINKS



MAPLE

Res:= NULL:
for x from 0 to 3^12 do
L:= convert(x, base, 3);
y:= add(L[i]*10^(i1), i=1..nops(L));
if issqr(y) then
Res:= Res, 2*sqrt(y)
fi
od:


PROG

(PARI) is_A202170(n)=!setminus(Set(Vec(Str(n^2))), Vec("048"))
(Magma) [ n: n in [0..10^6 by 2]  Set(Intseq(n^2)) subset [0, 4, 8] ]; // Bruno Berselli, Dec 19 2011


CROSSREFS



KEYWORD

nonn,base


AUTHOR



EXTENSIONS



STATUS

approved



