This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A089185 #9 Mar 19 2018 04:17:55 %S A089185 1,11,12,21,43,190,216,251,258,370,384,408,440,462,669,762,804,809, %T A089185 871,884,919,1188,1519,1520,1521,1790,1800,1875,2305,2312,2538,2997, %U A089185 3151,3210,3362,3474,4026,4561,5110,5490,5521,5569,5726,5762,5785,7216,7521 %N A089185 Numbers n with following property: suppose n^2 = d1 d2 d3 ...dk in decimal; then d1! + d2! + ... + dk! is a square. %H A089185 Robert Israel, <a href="/A089185/b089185.txt">Table of n, a(n) for n = 1..10000</a> %e A089185 a(4)=21: 21^2=441, (4!+4!+1!)^(1/2)=7. %p A089185 filter:= n -> issqr(add(d!, d=convert(n^2,base,10))): %p A089185 select(filter, [$1..10^4]); # _Robert Israel_, Mar 18 2018 %K A089185 nonn,base %O A089185 1,2 %A A089185 _Yalcin Aktar_, Dec 07 2003 %E A089185 More terms from _Yalcin Aktar_, Mar 02 2007