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 A061457 #39 Dec 08 2024 20:41:55
%S A061457 0,1,4,9,100,121,144,169,400,441,484,676,900,961,1089,9801,10000,
%T A061457 10201,10404,10609,12100,12321,12544,12769,14400,14641,14884,16900,
%U A061457 40000,40401,40804,44100,44521,44944,48400,48841,67600,69696,90000,90601
%N A061457 Squares whose reversal is also a square.
%C A061457 The corresponding square roots are in A102859.
%H A061457 Jon E. Schoenfield, <a href="/A061457/b061457.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Harry J. Smith)
%H A061457 <a href="/index/Sq#sqrev">Index entry for sequences related to reversing digits of squares</a>
%F A061457 a(n) = A102859(n)^2.
%e A061457 169 and 961 are both squares.
%e A061457 1089 = 33^2 and 9801 = 99^2 so 1089 and 9801 belong to the sequence.
%t A061457 Select[Range[0,400]^2,IntegerQ[Sqrt[IntegerReverse[#]]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 29 2019 *)
%o A061457 (PARI) { for(m=0, 1000, my(r=fromdigits(Vecrev(digits(m^2)))); if(issquare(r), print1(m^2, ", ") )) } \\ _Harry J. Smith_, Jul 23 2009
%o A061457 (Magma) [n^2: n in [0..306] | IsSquare(Seqint(Reverse(Intseq(n^2))))]; // _Bruno Berselli_, Apr 30 2011
%o A061457 (Python)
%o A061457 from itertools import count, islice
%o A061457 from sympy import integer_nthroot
%o A061457 def A061457_gen(): # generator of terms
%o A061457 return filter(lambda n:integer_nthroot(int(str(n)[::-1]),2)[1], (n**2 for n in count(0)))
%o A061457 A061457_list = list(islice(A061457_gen(),30)) # _Chai Wah Wu_, Nov 18 2022
%Y A061457 Cf. A102859 (square roots), A033294 (exclude final digit 0).
%K A061457 nonn,base,easy
%O A061457 1,3
%A A061457 _Amarnath Murthy_, May 03 2001
%E A061457 More terms from Larry Reeves (larryr(AT)acm.org), May 17 2001