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%I #9 Mar 19 2018 04:17:55
%S 1,11,12,21,43,190,216,251,258,370,384,408,440,462,669,762,804,809,
%T 871,884,919,1188,1519,1520,1521,1790,1800,1875,2305,2312,2538,2997,
%U 3151,3210,3362,3474,4026,4561,5110,5490,5521,5569,5726,5762,5785,7216,7521
%N Numbers n with following property: suppose n^2 = d1 d2 d3 ...dk in decimal; then d1! + d2! + ... + dk! is a square.
%H Robert Israel, <a href="/A089185/b089185.txt">Table of n, a(n) for n = 1..10000</a>
%e a(4)=21: 21^2=441, (4!+4!+1!)^(1/2)=7.
%p filter:= n -> issqr(add(d!, d=convert(n^2,base,10))):
%p select(filter, [$1..10^4]); # _Robert Israel_, Mar 18 2018
%K nonn,base
%O 1,2
%A _Yalcin Aktar_, Dec 07 2003
%E More terms from _Yalcin Aktar_, Mar 02 2007
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