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 A167042 #14 Mar 15 2024 02:24:19 %S A167042 225,5625,22500,562500,2250000,6125625,19580625,56250000,225000000, %T A167042 612562500,1958062500,2562890625,5625000000,22500000000,51472265625, %U A167042 61256250000,195806250000,256289062500,562500000000,2250000000000,5147226562500,6125625000000 %N A167042 Squares that remain squares when prefixed with a 7. %H A167042 Chai Wah Wu, <a href="/A167042/b167042.txt">Table of n, a(n) for n = 1..1000</a> %e A167042 225 = 15^2 is a square, and becomes the square 7225 = 85^2 if prefixed with a 7. %t A167042 Select[Range[25*10^5]^2,IntegerQ[Sqrt[#+7*10^IntegerLength[#]]]&] (* _Harvey P. Dale_, Mar 02 2015 *) %K A167042 nonn,base %O A167042 1,1 %A A167042 _Claudio Meller_, Oct 27 2009 %E A167042 Keyword:base added by _R. J. Mathar_, Oct 28 2009 %E A167042 More terms from _Chai Wah Wu_, Sep 11 2014