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A061457 Numbers n such that n and its reversal are both squares. 7

%I

%S 0,1,4,9,100,121,144,169,400,441,484,676,900,961,1089,9801,10000,

%T 10201,10404,10609,12100,12321,12544,12769,14400,14641,14884,16900,

%U 40000,40401,40804,44100,44521,44944,48400,48841,67600,69696,90000,90601

%N Numbers n such that n and its reversal are both squares.

%H Harry J. Smith, <a href="/A061457/b061457.txt">Table of n, a(n) for n=1..1000</a>

%e 169 and 961 are both squares.

%e 1089 = 33^2 and 9801 = 99^2 so 1089 and 9801 belong to the sequence.

%t Select[Range[0,400]^2,IntegerQ[Sqrt[IntegerReverse[#]]]&] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jul 29 2019 *)

%o (PARI) { n=0; for (m=0, 1110100, x=m^2; r=0; while (x>0, d=x-10*(x\10); x\=10; r=r*10 + d); if (issquare(r), write("b061457.txt", n++, " ", m^2)) ) } \\ _Harry J. Smith_, Jul 23 2009

%o (MAGMA) [n^2: n in [0..306] | IsSquare(Seqint(Reverse(Intseq(n^2))))]; // _Bruno Berselli_, Apr 30 2011

%K nonn,base,easy

%O 1,3

%A _Amarnath Murthy_, May 03 2001

%E More terms from Larry Reeves (larryr(AT)acm.org), May 17 2001

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Last modified January 27 04:57 EST 2020. Contains 331291 sequences. (Running on oeis4.)